How to detect Windows 64-bit platform with NET

Question

In a  NET 2 0 C  application I use the following code to detect the operating system platform   string os platform   System Environment OSVersion Platform ToString      This returns  Win32NT   The problem is that it returns  Win32NT  even when running on Windows Vista 64-bit   Is there any other method to know the correct platform  32 nbsp or 64 nbsp bit    Note that it should also detect 64 nbsp bit when run as a 32 nbsp bit application on Windows 64 nbsp bit

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The full answer is this  taken from both stefan-mg  ripper234 and BobbyShaftoe s answer         DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi        return  MarshalAs UnmanagedType Bool       public static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool lpSystemInfo        private bool Is64Bit                 if  IntPtr Size    8     IntPtr Size    4  amp  amp  Is32BitProcessOn64BitProcessor                           return true                    else                       return false                       private bool Is32BitProcessOn64BitProcessor                 bool retVal           IsWow64Process Process GetCurrentProcess   Handle  out retVal            return retVal           First check if you re in a 64 bit process  If you re not  check if the 32 bit process is a Wow64Process

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Microsoft has put a code sample for this   http   1code codeplex com SourceControl changeset view 39074 842775  It looks like this            lt summary gt          The function determines whether the current operating system is a          64-bit operating system           lt  summary gt           lt returns gt          The function returns true if the operating system is 64-bit           otherwise  it returns false           lt  returns gt      public static bool Is64BitOperatingSystem                 if  IntPtr Size    8      64-bit programs run only on Win64                       return true                    else     32-bit programs run on both 32-bit and 64-bit Windows                          Detect whether the current process is a 32-bit process                 running on a 64-bit system              bool flag              return   DoesWin32MethodExist  kernel32 dll    IsWow64Process    amp  amp                  IsWow64Process GetCurrentProcess    out flag    amp  amp  flag                             lt summary gt          The function determins whether a method exists in the export          table of a certain module           lt  summary gt           lt param name  moduleName  gt The name of the module lt  param gt           lt param name  methodName  gt The name of the method lt  param gt           lt returns gt          The function returns true if the method specified by methodName          exists in the export table of the module specified by moduleName           lt  returns gt      static bool DoesWin32MethodExist string moduleName  string methodName                IntPtr moduleHandle   GetModuleHandle moduleName           if  moduleHandle    IntPtr Zero                        return false                    return  GetProcAddress moduleHandle  methodName     IntPtr Zero               DllImport  kernel32 dll        static extern IntPtr GetCurrentProcess          DllImport  kernel32 dll   CharSet   CharSet Auto       static extern IntPtr GetModuleHandle string moduleName         DllImport  kernel32   CharSet   CharSet Auto  SetLastError   true       static extern IntPtr GetProcAddress IntPtr hModule           MarshalAs UnmanagedType LPStr  string procName         DllImport  kernel32 dll   CharSet   CharSet Auto  SetLastError   true        return  MarshalAs UnmanagedType Bool       static extern bool IsWow64Process IntPtr hProcess  out bool wow64Process     There is a WMI version available as well  for testing remote machines

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foobar  You are right  it is too easy     In 99  of the cases  developers with weak system administrator backgrounds ultimately fail to realize the power Microsoft has always provided for anyone to enumerate Windows   System administrators will always write better and simpler code when it comes to such a point   Nevertheless  one thing to note  build configuration must be AnyCPU for this environment variable to return the correct values on the correct systems   System Environment GetEnvironmentVariable  PROCESSOR ARCHITECTURE     This will return  X86  on 32-bit Windows  and  AMD64  on 64-bit Windows

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UPDATE  As Joel Coehoorn and others suggest  starting at  NET Framework 4 0  you can just check Environment Is64BitOperatingSystem   IntPtr Size won t return the correct value if running in 32-bit  NET Framework 2 0 on 64-bit Windows  it would return 32-bit   As Microsoft s Raymond Chen describes  you have to first check if running in a 64-bit process  I think in  NET you can do so by checking IntPtr Size   and if you are running in a 32-bit process  you still have to call the Win API function IsWow64Process  If this returns true  you are running in a 32-bit process on 64-bit Windows  Microsoft s Raymond Chen  How to detect programmatically whether you are running on 64-bit Windows My solution  static bool is64BitProcess    IntPtr Size    8   static bool is64BitOperatingSystem   is64BitProcess    InternalCheckIsWow64      DllImport  quot kernel32 dll quot   SetLastError   true  CallingConvention   CallingConvention Winapi    return  MarshalAs UnmanagedType Bool   private static extern bool IsWow64Process       In  IntPtr hProcess       Out  out bool wow64Process     public static bool InternalCheckIsWow64         if   Environment OSVersion Version Major    5  amp  amp  Environment OSVersion Version Minor  gt   1             Environment OSVersion Version Major  gt   6                using  Process p   Process GetCurrentProcess                          bool retVal              if   IsWow64Process p Handle  out retVal                                 return false                            return retVal                      else               return false

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Use these two environment variables  pseudo code    if  PROCESSOR ARCHITECTURE   x86  amp  amp      isDefined PROCESSOR ARCHITEW6432   amp  amp      PROCESSOR ARCHITEW6432   AMD64           64 bit OS   else     if  PROCESSOR ARCHITECTURE   AMD64              64 bit OS           else         if  PROCESSOR ARCHITECTURE   x86                  32 bit OS             Refer to the blog post HOWTO  Detect Process Bitness

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Given that the accepted answer is very complex  There are simpler ways  Mine is a variation of alexandrudicu s anaswer  Given that 64-bit windows install 32-bit applications in Program Files  x86  you can check if that folder exists  using environment variables  to make up for different localizations   e g    private bool Is64BitSystem      get            return Directory Exists Environment ExpandEnvironmentVariables    PROGRAMFILES X86                This for me is faster and simpler  Given that I also wish to access a specific path under that folder based on OS version

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I use   Dim drivelet As String   Application StartupPath ToString If Directory Exists drivelet 0   amp     Program Files  x86    Then     MsgBox  64bit   Else     MsgBox  32bit   End if   This gets the path where your application is launched in case you have it installed in various places on the computer  Also  you could just do the general C   path since 99 9  of computers out there have Windows installed in C

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Given that the accepted answer is very complex  There are simpler ways  Mine is a variation of alexandrudicu s anaswer  Given that 64-bit windows install 32-bit applications in Program Files  x86  you can check if that folder exists  using environment variables  to make up for different localizations   e g    private bool Is64BitSystem      get            return Directory Exists Environment ExpandEnvironmentVariables    PROGRAMFILES X86                This for me is faster and simpler  Given that I also wish to access a specific path under that folder based on OS version

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You can also check for the PROCESSOR ARCHITECTURE environment variable   It either doesn t exist or is set to  x86  on 32-bit Windows   private int GetOSArchitecture         string pa            Environment GetEnvironmentVariable  PROCESSOR ARCHITECTURE        return   String IsNullOrEmpty pa                   String Compare pa  0   x86   0  3  true     0    32   64

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Use these two environment variables  pseudo code    if  PROCESSOR ARCHITECTURE   x86  amp  amp      isDefined PROCESSOR ARCHITEW6432   amp  amp      PROCESSOR ARCHITEW6432   AMD64           64 bit OS   else     if  PROCESSOR ARCHITECTURE   AMD64              64 bit OS           else         if  PROCESSOR ARCHITECTURE   x86                  32 bit OS             Refer to the blog post HOWTO  Detect Process Bitness

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Quickest way   if IntPtr Size    8           64 bit machine   else if IntPtr Size    4            32 bit machine      Note  this is very direct and works correctly on 64-bit only if the program does not force execution as a 32-bit process  e g  through  lt Prefer32Bit gt true lt  Prefer32Bit gt  in the project settings

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Here is the direct approach in C  using DllImport from this page    DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi     return  MarshalAs UnmanagedType Bool    public static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool lpSystemInfo     public static bool Is64Bit           bool retVal        IsWow64Process Process GetCurrentProcess   Handle  out retVal         return retVal

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This is a solution based on Microsoft s code at http   1code codeplex com SourceControl changeset view 39074 842775  It uses extension methods for easy code reuse   Some possible usage is shown below   bool bIs64BitOS   System Environment OSVersion IsWin64BitOS     bool bIs64BitProc   System Diagnostics Process GetCurrentProcess   Is64BitProc       Hosts the extension methods   public static class OSHelperTools                lt summary gt               The function determines whether the current operating system is a               64-bit operating system                lt  summary gt                lt returns gt               The function returns true if the operating system is 64-bit                otherwise  it returns false                lt  returns gt          public static bool IsWin64BitOS this OperatingSystem os                    if  IntPtr Size    8               64-bit programs run only on Win64                        return true             else   32-bit programs run on both 32-bit and 64-bit Windows                     Detect whether the current process is a 32-bit process                                running on a 64-bit system                             return Process GetCurrentProcess   Is64BitProc                                    lt summary gt            Checks if the process is 64 bit            lt  summary gt             lt param name  os  gt  lt  param gt             lt returns gt            The function returns true if the process is 64-bit                  otherwise  it returns false             lt  returns gt          public static bool Is64BitProc this System Diagnostics Process p                       32-bit programs run on both 32-bit and 64-bit Windows                       Detect whether the current process is a 32-bit process                            running on a 64-bit system                         bool result            return   DoesWin32MethodExist  kernel32 dll    IsWow64Process    amp  amp  IsWow64Process p Handle  out result    amp  amp  result                       lt summary gt               The function determins whether a method exists in the export               table of a certain module                lt  summary gt                lt param name  moduleName  gt The name of the module lt  param gt                lt param name  methodName  gt The name of the method lt  param gt                lt returns gt               The function returns true if the method specified by methodName               exists in the export table of the module specified by moduleName                lt  returns gt             static bool DoesWin32MethodExist string moduleName  string methodName                    IntPtr moduleHandle   GetModuleHandle moduleName             if  moduleHandle    IntPtr Zero                return false              return  GetProcAddress moduleHandle  methodName     IntPtr Zero                   DllImport  kernel32 dll          static extern IntPtr GetCurrentProcess            DllImport  kernel32 dll   CharSet   CharSet Auto         static extern IntPtr GetModuleHandle string moduleName           DllImport  kernel32   CharSet   CharSet Auto  SetLastError   true         static extern IntPtr GetProcAddress IntPtr hModule   MarshalAs UnmanagedType LPStr  string procName           DllImport  kernel32 dll   CharSet   CharSet Auto  SetLastError   true          return  MarshalAs UnmanagedType Bool         static extern bool IsWow64Process IntPtr hProcess  out bool wow64Process

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Include the following code into a class in your project        DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi        return  MarshalAs UnmanagedType Bool       private static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool wow64Process        public static int GetBit                 int MethodResult               try                       int Architecture   32               if   Environment OSVersion Version Major    5  amp  amp  Environment OSVersion Version Minor  gt   1     Environment OSVersion Version Major  gt   6                                using  Process p   Process GetCurrentProcess                                          bool Is64Bit                       if  IsWow64Process p Handle  out Is64Bit                                                 if  Is64Bit                                                        Architecture   64                                                                                                   MethodResult   Architecture                     catch    Exception ex                          ex HandleException                      return MethodResult          Use it like so   string Architecture    This is a     GetBit      bit machine

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Microsoft has put a code sample for this   http   1code codeplex com SourceControl changeset view 39074 842775  It looks like this            lt summary gt          The function determines whether the current operating system is a          64-bit operating system           lt  summary gt           lt returns gt          The function returns true if the operating system is 64-bit           otherwise  it returns false           lt  returns gt      public static bool Is64BitOperatingSystem                 if  IntPtr Size    8      64-bit programs run only on Win64                       return true                    else     32-bit programs run on both 32-bit and 64-bit Windows                          Detect whether the current process is a 32-bit process                 running on a 64-bit system              bool flag              return   DoesWin32MethodExist  kernel32 dll    IsWow64Process    amp  amp                  IsWow64Process GetCurrentProcess    out flag    amp  amp  flag                             lt summary gt          The function determins whether a method exists in the export          table of a certain module           lt  summary gt           lt param name  moduleName  gt The name of the module lt  param gt           lt param name  methodName  gt The name of the method lt  param gt           lt returns gt          The function returns true if the method specified by methodName          exists in the export table of the module specified by moduleName           lt  returns gt      static bool DoesWin32MethodExist string moduleName  string methodName                IntPtr moduleHandle   GetModuleHandle moduleName           if  moduleHandle    IntPtr Zero                        return false                    return  GetProcAddress moduleHandle  methodName     IntPtr Zero               DllImport  kernel32 dll        static extern IntPtr GetCurrentProcess          DllImport  kernel32 dll   CharSet   CharSet Auto       static extern IntPtr GetModuleHandle string moduleName         DllImport  kernel32   CharSet   CharSet Auto  SetLastError   true       static extern IntPtr GetProcAddress IntPtr hModule           MarshalAs UnmanagedType LPStr  string procName         DllImport  kernel32 dll   CharSet   CharSet Auto  SetLastError   true        return  MarshalAs UnmanagedType Bool       static extern bool IsWow64Process IntPtr hProcess  out bool wow64Process     There is a WMI version available as well  for testing remote machines

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Use this to get the installed Windows architecture   string getOSArchitecture         string architectureStr      if  Directory Exists Environment GetFolderPath                             Environment SpecialFolder ProgramFilesX86              architectureStr   64-bit             else           architectureStr    32-bit             return architectureStr

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Quickest way   if IntPtr Size    8           64 bit machine   else if IntPtr Size    4            32 bit machine      Note  this is very direct and works correctly on 64-bit only if the program does not force execution as a 32-bit process  e g  through  lt Prefer32Bit gt true lt  Prefer32Bit gt  in the project settings

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Quickest way   if IntPtr Size    8           64 bit machine   else if IntPtr Size    4            32 bit machine      Note  this is very direct and works correctly on 64-bit only if the program does not force execution as a 32-bit process  e g  through  lt Prefer32Bit gt true lt  Prefer32Bit gt  in the project settings

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I found this to be the best way to check for the platform of the system and the process   bool 64BitSystem   Environment Is64BitOperatingSystem  bool 64BitProcess   Environment Is64BitProcess    The first property returns true for 64-bit system  and false for 32-bit  The second property returns true for 64-bit process  and false for 32-bit   The need for these two properties is because you can run 32-bit processes on 64-bit system  so you will need to check for both the system and the process

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If you re using  NET Framework 4 0  it s easy   Environment Is64BitOperatingSystem   See Environment Is64BitOperatingSystem Property   MSDN

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OSInfo Bits  using System  namespace CSharp411       class Program               static void Main  string   args                        Console WriteLine   Operation System Information                Console WriteLine   ----------------------------                Console WriteLine   Name    0    OSInfo Name               Console WriteLine   Edition    0    OSInfo Edition               Console WriteLine   Service Pack    0    OSInfo ServicePack               Console WriteLine   Version    0    OSInfo VersionString               Console WriteLine   Bits    0    OSInfo Bits               Console ReadLine

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Try this   Environment Is64BitOperatingSystem  Environment Is64BitProcess

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I m using the followin code  Note  It s made for an AnyCPU project       public static bool Is32bitProcess Process proc            if   IsThis64bitProcess    return true     We re in 32-bit mode  so all are 32-bit           foreach  ProcessModule module in proc Modules                try                   string fname   Path GetFileName module FileName  ToLowerInvariant                    if  fname Contains  wow64                          return true                                  catch                      What on earth is going on here                                  return false             public static bool Is64bitProcess Process proc            return  Is32bitProcess proc              public static bool IsThis64bitProcess             return  IntPtr Size    8

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The full answer is this  taken from both stefan-mg  ripper234 and BobbyShaftoe s answer         DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi        return  MarshalAs UnmanagedType Bool       public static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool lpSystemInfo        private bool Is64Bit                 if  IntPtr Size    8     IntPtr Size    4  amp  amp  Is32BitProcessOn64BitProcessor                           return true                    else                       return false                       private bool Is32BitProcessOn64BitProcessor                 bool retVal           IsWow64Process Process GetCurrentProcess   Handle  out retVal            return retVal           First check if you re in a 64 bit process  If you re not  check if the 32 bit process is a Wow64Process

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From Chriz Yuen blog  C   Net 4 0 Introduced two new environment property Environment Is64BitOperatingSystem  Environment Is64BitProcess   Please be careful when you use these both property   Test on Windows 7 64bits Machine     Workspace  Target Platform x86 Environment Is64BitOperatingSystem True Environment Is64BitProcess False    Workspace  Target Platform x64 Environment Is64BitOperatingSystem True Environment Is64BitProcess True    Workspace  Target Platform Any Environment Is64BitOperatingSystem True Environment Is64BitProcess True

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Enjoy  -   Function Is64Bit   As Boolean      Return My Computer FileSystem SpecialDirectories ProgramFiles Contains  Program Files  x86     End Function

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I use a version of the following       public static bool Is64BitSystem                 if  Directory Exists Environment GetEnvironmentVariable  Program Files  x86      return true          else return false

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This is a solution based on Microsoft s code at http   1code codeplex com SourceControl changeset view 39074 842775  It uses extension methods for easy code reuse   Some possible usage is shown below   bool bIs64BitOS   System Environment OSVersion IsWin64BitOS     bool bIs64BitProc   System Diagnostics Process GetCurrentProcess   Is64BitProc       Hosts the extension methods   public static class OSHelperTools                lt summary gt               The function determines whether the current operating system is a               64-bit operating system                lt  summary gt                lt returns gt               The function returns true if the operating system is 64-bit                otherwise  it returns false                lt  returns gt          public static bool IsWin64BitOS this OperatingSystem os                    if  IntPtr Size    8               64-bit programs run only on Win64                        return true             else   32-bit programs run on both 32-bit and 64-bit Windows                     Detect whether the current process is a 32-bit process                                running on a 64-bit system                             return Process GetCurrentProcess   Is64BitProc                                    lt summary gt            Checks if the process is 64 bit            lt  summary gt             lt param name  os  gt  lt  param gt             lt returns gt            The function returns true if the process is 64-bit                  otherwise  it returns false             lt  returns gt          public static bool Is64BitProc this System Diagnostics Process p                       32-bit programs run on both 32-bit and 64-bit Windows                       Detect whether the current process is a 32-bit process                            running on a 64-bit system                         bool result            return   DoesWin32MethodExist  kernel32 dll    IsWow64Process    amp  amp  IsWow64Process p Handle  out result    amp  amp  result                       lt summary gt               The function determins whether a method exists in the export               table of a certain module                lt  summary gt                lt param name  moduleName  gt The name of the module lt  param gt                lt param name  methodName  gt The name of the method lt  param gt                lt returns gt               The function returns true if the method specified by methodName               exists in the export table of the module specified by moduleName                lt  returns gt             static bool DoesWin32MethodExist string moduleName  string methodName                    IntPtr moduleHandle   GetModuleHandle moduleName             if  moduleHandle    IntPtr Zero                return false              return  GetProcAddress moduleHandle  methodName     IntPtr Zero                   DllImport  kernel32 dll          static extern IntPtr GetCurrentProcess            DllImport  kernel32 dll   CharSet   CharSet Auto         static extern IntPtr GetModuleHandle string moduleName           DllImport  kernel32   CharSet   CharSet Auto  SetLastError   true         static extern IntPtr GetProcAddress IntPtr hModule   MarshalAs UnmanagedType LPStr  string procName           DllImport  kernel32 dll   CharSet   CharSet Auto  SetLastError   true          return  MarshalAs UnmanagedType Bool         static extern bool IsWow64Process IntPtr hProcess  out bool wow64Process

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UPDATE  As Joel Coehoorn and others suggest  starting at  NET Framework 4 0  you can just check Environment Is64BitOperatingSystem   IntPtr Size won t return the correct value if running in 32-bit  NET Framework 2 0 on 64-bit Windows  it would return 32-bit   As Microsoft s Raymond Chen describes  you have to first check if running in a 64-bit process  I think in  NET you can do so by checking IntPtr Size   and if you are running in a 32-bit process  you still have to call the Win API function IsWow64Process  If this returns true  you are running in a 32-bit process on 64-bit Windows  Microsoft s Raymond Chen  How to detect programmatically whether you are running on 64-bit Windows My solution  static bool is64BitProcess    IntPtr Size    8   static bool is64BitOperatingSystem   is64BitProcess    InternalCheckIsWow64      DllImport  quot kernel32 dll quot   SetLastError   true  CallingConvention   CallingConvention Winapi    return  MarshalAs UnmanagedType Bool   private static extern bool IsWow64Process       In  IntPtr hProcess       Out  out bool wow64Process     public static bool InternalCheckIsWow64         if   Environment OSVersion Version Major    5  amp  amp  Environment OSVersion Version Minor  gt   1             Environment OSVersion Version Major  gt   6                using  Process p   Process GetCurrentProcess                          bool retVal              if   IsWow64Process p Handle  out retVal                                 return false                            return retVal                      else               return false

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Here s a Windows Management Instrumentation  WMI  approach   string  osVersion       string  osServicePack       string  osArchitecture        ManagementObjectSearcher searcher   new ManagementObjectSearcher  select   from Win32 OperatingSystem    ManagementObjectCollection collection   searcher Get     foreach  ManagementObject mbo in collection         osVersion   mbo GetPropertyValue  Caption   ToString         osServicePack   string Format   0   1    mbo GetPropertyValue  ServicePackMajorVersion   ToString    mbo GetPropertyValue  ServicePackMinorVersion   ToString          try                osArchitecture   mbo GetPropertyValue  OSArchitecture   ToString              catch                  OSArchitecture only supported on Windows 7 Windows Server 2008          Console WriteLine  osVersion            osVersion   Console WriteLine  osServicePack        osServicePack   Console WriteLine  osArchitecture       osArchitecture                                                 Test on Windows 7 64-bit       osVersion       Microsoft Windows 7 Professional    osservicePack   1 0    osArchitecture  64-bit                                               Test on Windows Server 2008 64-bit       --The extra r s come from the registered trademark       osVersion       Microsoftr Windows Serverr 2008 Standard    osServicePack   1 0    osArchitecture  64-bit                                               Test on Windows Server 2003 32-bit       --OSArchitecture property not supported on W2K3       osVersion       Microsoft R  Windows R  Server 2003  Standard Edition    osServicePack   2 0    osArchitecture

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This is just an implementation of what s suggested above by Bruno Lopez  but works on Win2k   all WinXP service packs  Just figured I d post it so other people didn t have roll it by hand   would have posted as a comment  but I m a new user     DllImport  kernel32   SetLastError   true  CallingConvention   CallingConvention Winapi   public extern static IntPtr LoadLibrary string libraryName     DllImport  kernel32   SetLastError   true  CallingConvention   CallingConvention Winapi   public extern static IntPtr GetProcAddress IntPtr hwnd  string procedureName    private delegate bool IsWow64ProcessDelegate  In  IntPtr handle   Out  out bool isWow64Process    public static bool IsOS64Bit         if  IntPtr Size    8     IntPtr Size    4  amp  amp  Is32BitProcessOn64BitProcessor                   return true            else               return false           private static IsWow64ProcessDelegate GetIsWow64ProcessDelegate       IntPtr handle   LoadLibrary  kernel32       if   handle    IntPtr Zero          IntPtr fnPtr   GetProcAddress handle   IsWow64Process         if  fnPtr    IntPtr Zero              return  IsWow64ProcessDelegate Marshal GetDelegateForFunctionPointer  IntPtr fnPtr  typeof IsWow64ProcessDelegate                 return null     private static bool Is32BitProcessOn64BitProcessor       IsWow64ProcessDelegate fnDelegate   GetIsWow64ProcessDelegate       if  fnDelegate    null          return false         bool isWow64    bool retVal   fnDelegate Invoke Process GetCurrentProcess   Handle  out isWow64      if  retVal    false          return false         return isWow64

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Use this to get the installed Windows architecture   string getOSArchitecture         string architectureStr      if  Directory Exists Environment GetFolderPath                             Environment SpecialFolder ProgramFilesX86              architectureStr   64-bit             else           architectureStr    32-bit             return architectureStr

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NET 4 has two new properties in the Environment class  Is64BitProcess and Is64BitOperatingSystem  Interestingly  if you use Reflector you can see they are implemented differently in the 32-bit  amp  64-bit versions of mscorlib  The 32-bit version returns false for Is64BitProcess and calls IsWow64Process via P Invoke for Is64BitOperatingSystem  The 64-bit version just returns true for both

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I used this check with success on many operating systems   private bool Is64BitSystem      get            return Directory Exists Environment ExpandEnvironmentVariables    windir  SysWOW64              This folder is always named  SysWOW64   no matter of the language of the operating system  This works for  NET Framework 1 1 or above

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Just see if the  C  Program Files  x86   exists  If not  then you are on a 32 bit OS  If it does  then the OS is 64 bit  Windows nbsp Vista or Windows nbsp 7   It seems simple enough

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Using dotPeek helps to see how the framework actually does it  With that in mind  here s what I ve come up with   public static class EnvironmentHelper        DllImport  kernel32 dll        static extern IntPtr GetCurrentProcess          DllImport  kernel32 dll        static extern IntPtr GetModuleHandle string moduleName         DllImport  kernel32        static extern IntPtr GetProcAddress IntPtr hModule  string procName         DllImport  kernel32 dll        static extern bool IsWow64Process IntPtr hProcess  out bool wow64Process        public static bool Is64BitOperatingSystem                    Check if this process is natively an x64 process  If it is  it will only run on x64 environments  thus  the environment must be x64          if  IntPtr Size    8              return true             Check if this process is an x86 process running on an x64 environment          IntPtr moduleHandle   GetModuleHandle  kernel32            if  moduleHandle    IntPtr Zero                        IntPtr processAddress   GetProcAddress moduleHandle   IsWow64Process                if  processAddress    IntPtr Zero                                bool result                  if  IsWow64Process GetCurrentProcess    out result   amp  amp  result                      return true                                     The environment must be an x86 environment          return false            Example usage   EnvironmentHelper Is64BitOperatingSystem

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Here is the direct approach in C  using DllImport from this page    DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi     return  MarshalAs UnmanagedType Bool    public static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool lpSystemInfo     public static bool Is64Bit           bool retVal        IsWow64Process Process GetCurrentProcess   Handle  out retVal         return retVal

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Here is the direct approach in C  using DllImport from this page    DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi     return  MarshalAs UnmanagedType Bool    public static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool lpSystemInfo     public static bool Is64Bit           bool retVal        IsWow64Process Process GetCurrentProcess   Handle  out retVal         return retVal

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UPDATE  As Joel Coehoorn and others suggest  starting at  NET Framework 4 0  you can just check Environment Is64BitOperatingSystem   IntPtr Size won t return the correct value if running in 32-bit  NET Framework 2 0 on 64-bit Windows  it would return 32-bit   As Microsoft s Raymond Chen describes  you have to first check if running in a 64-bit process  I think in  NET you can do so by checking IntPtr Size   and if you are running in a 32-bit process  you still have to call the Win API function IsWow64Process  If this returns true  you are running in a 32-bit process on 64-bit Windows  Microsoft s Raymond Chen  How to detect programmatically whether you are running on 64-bit Windows My solution  static bool is64BitProcess    IntPtr Size    8   static bool is64BitOperatingSystem   is64BitProcess    InternalCheckIsWow64      DllImport  quot kernel32 dll quot   SetLastError   true  CallingConvention   CallingConvention Winapi    return  MarshalAs UnmanagedType Bool   private static extern bool IsWow64Process       In  IntPtr hProcess       Out  out bool wow64Process     public static bool InternalCheckIsWow64         if   Environment OSVersion Version Major    5  amp  amp  Environment OSVersion Version Minor  gt   1             Environment OSVersion Version Major  gt   6                using  Process p   Process GetCurrentProcess                          bool retVal              if   IsWow64Process p Handle  out retVal                                 return false                            return retVal                      else               return false

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I m using the followin code  Note  It s made for an AnyCPU project       public static bool Is32bitProcess Process proc            if   IsThis64bitProcess    return true     We re in 32-bit mode  so all are 32-bit           foreach  ProcessModule module in proc Modules                try                   string fname   Path GetFileName module FileName  ToLowerInvariant                    if  fname Contains  wow64                          return true                                  catch                      What on earth is going on here                                  return false             public static bool Is64bitProcess Process proc            return  Is32bitProcess proc              public static bool IsThis64bitProcess             return  IntPtr Size    8

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I use   Dim drivelet As String   Application StartupPath ToString If Directory Exists drivelet 0   amp     Program Files  x86    Then     MsgBox  64bit   Else     MsgBox  32bit   End if   This gets the path where your application is launched in case you have it installed in various places on the computer  Also  you could just do the general C   path since 99 9  of computers out there have Windows installed in C

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From Chriz Yuen blog  C   Net 4 0 Introduced two new environment property Environment Is64BitOperatingSystem  Environment Is64BitProcess   Please be careful when you use these both property   Test on Windows 7 64bits Machine     Workspace  Target Platform x86 Environment Is64BitOperatingSystem True Environment Is64BitProcess False    Workspace  Target Platform x64 Environment Is64BitOperatingSystem True Environment Is64BitProcess True    Workspace  Target Platform Any Environment Is64BitOperatingSystem True Environment Is64BitProcess True

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Quickest way   if IntPtr Size    8           64 bit machine   else if IntPtr Size    4            32 bit machine      Note  this is very direct and works correctly on 64-bit only if the program does not force execution as a 32-bit process  e g  through  lt Prefer32Bit gt true lt  Prefer32Bit gt  in the project settings

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Here is the direct approach in C  using DllImport from this page    DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi     return  MarshalAs UnmanagedType Bool    public static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool lpSystemInfo     public static bool Is64Bit           bool retVal        IsWow64Process Process GetCurrentProcess   Handle  out retVal         return retVal

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Enjoy  -   Function Is64Bit   As Boolean      Return My Computer FileSystem SpecialDirectories ProgramFiles Contains  Program Files  x86     End Function

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This question is for  NET 2 0 but still comes up in a google search  and nobody here mentionned that since  NET standard 1 1    NET core 1 0  there is now a better way to know the CPU architecture  System Runtime InteropServices RuntimeInformation ProcessArchitecture  This should theoretically be able to differenciate between x64 and Arm64  though I didn t test it myself  See the documentation

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I found this to be the best way to check for the platform of the system and the process   bool 64BitSystem   Environment Is64BitOperatingSystem  bool 64BitProcess   Environment Is64BitProcess    The first property returns true for 64-bit system  and false for 32-bit  The second property returns true for 64-bit process  and false for 32-bit   The need for these two properties is because you can run 32-bit processes on 64-bit system  so you will need to check for both the system and the process

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If you re using  NET Framework 4 0  it s easy   Environment Is64BitOperatingSystem   See Environment Is64BitOperatingSystem Property   MSDN

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I used this check with success on many operating systems   private bool Is64BitSystem      get            return Directory Exists Environment ExpandEnvironmentVariables    windir  SysWOW64              This folder is always named  SysWOW64   no matter of the language of the operating system  This works for  NET Framework 1 1 or above

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Include the following code into a class in your project        DllImport  kernel32 dll   SetLastError   true  CallingConvention   CallingConvention Winapi        return  MarshalAs UnmanagedType Bool       private static extern bool IsWow64Process  In  IntPtr hProcess   Out  out bool wow64Process        public static int GetBit                 int MethodResult               try                       int Architecture   32               if   Environment OSVersion Version Major    5  amp  amp  Environment OSVersion Version Minor  gt   1     Environment OSVersion Version Major  gt   6                                using  Process p   Process GetCurrentProcess                                          bool Is64Bit                       if  IsWow64Process p Handle  out Is64Bit                                                 if  Is64Bit                                                        Architecture   64                                                                                                   MethodResult   Architecture                     catch    Exception ex                          ex HandleException                      return MethodResult          Use it like so   string Architecture    This is a     GetBit      bit machine

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Using dotPeek helps to see how the framework actually does it  With that in mind  here s what I ve come up with   public static class EnvironmentHelper        DllImport  kernel32 dll        static extern IntPtr GetCurrentProcess          DllImport  kernel32 dll        static extern IntPtr GetModuleHandle string moduleName         DllImport  kernel32        static extern IntPtr GetProcAddress IntPtr hModule  string procName         DllImport  kernel32 dll        static extern bool IsWow64Process IntPtr hProcess  out bool wow64Process        public static bool Is64BitOperatingSystem                    Check if this process is natively an x64 process  If it is  it will only run on x64 environments  thus  the environment must be x64          if  IntPtr Size    8              return true             Check if this process is an x86 process running on an x64 environment          IntPtr moduleHandle   GetModuleHandle  kernel32            if  moduleHandle    IntPtr Zero                        IntPtr processAddress   GetProcAddress moduleHandle   IsWow64Process                if  processAddress    IntPtr Zero                                bool result                  if  IsWow64Process GetCurrentProcess    out result   amp  amp  result                      return true                                     The environment must be an x86 environment          return false            Example usage   EnvironmentHelper Is64BitOperatingSystem

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Here s a Windows Management Instrumentation  WMI  approach   string  osVersion       string  osServicePack       string  osArchitecture        ManagementObjectSearcher searcher   new ManagementObjectSearcher  select   from Win32 OperatingSystem    ManagementObjectCollection collection   searcher Get     foreach  ManagementObject mbo in collection         osVersion   mbo GetPropertyValue  Caption   ToString         osServicePack   string Format   0   1    mbo GetPropertyValue  ServicePackMajorVersion   ToString    mbo GetPropertyValue  ServicePackMinorVersion   ToString          try                osArchitecture   mbo GetPropertyValue  OSArchitecture   ToString              catch                  OSArchitecture only supported on Windows 7 Windows Server 2008          Console WriteLine  osVersion            osVersion   Console WriteLine  osServicePack        osServicePack   Console WriteLine  osArchitecture       osArchitecture                                                 Test on Windows 7 64-bit       osVersion       Microsoft Windows 7 Professional    osservicePack   1 0    osArchitecture  64-bit                                               Test on Windows Server 2008 64-bit       --The extra r s come from the registered trademark       osVersion       Microsoftr Windows Serverr 2008 Standard    osServicePack   1 0    osArchitecture  64-bit                                               Test on Windows Server 2003 32-bit       --OSArchitecture property not supported on W2K3       osVersion       Microsoft R  Windows R  Server 2003  Standard Edition    osServicePack   2 0    osArchitecture

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Just see if the  C  Program Files  x86   exists  If not  then you are on a 32 bit OS  If it does  then the OS is 64 bit  Windows nbsp Vista or Windows nbsp 7   It seems simple enough

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This question is for  NET 2 0 but still comes up in a google search  and nobody here mentionned that since  NET standard 1 1    NET core 1 0  there is now a better way to know the CPU architecture  System Runtime InteropServices RuntimeInformation ProcessArchitecture  This should theoretically be able to differenciate between x64 and Arm64  though I didn t test it myself  See the documentation

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You can also check for the PROCESSOR ARCHITECTURE environment variable   It either doesn t exist or is set to  x86  on 32-bit Windows   private int GetOSArchitecture         string pa            Environment GetEnvironmentVariable  PROCESSOR ARCHITECTURE        return   String IsNullOrEmpty pa                   String Compare pa  0   x86   0  3  true     0    32   64

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Try this   Environment Is64BitOperatingSystem  Environment Is64BitProcess

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I need to do this  but I also need to be able as an admin do it remotely  either case this seems to work quite nicely for me       public static bool is64bit String host                using  var reg   RegistryKey OpenRemoteBaseKey RegistryHive LocalMachine  host           using  var key   reg OpenSubKey   Software Microsoft Windows CurrentVersion                           return key GetValue  ProgramFilesDir  x86      null

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OSInfo Bits  using System  namespace CSharp411       class Program               static void Main  string   args                        Console WriteLine   Operation System Information                Console WriteLine   ----------------------------                Console WriteLine   Name    0    OSInfo Name               Console WriteLine   Edition    0    OSInfo Edition               Console WriteLine   Service Pack    0    OSInfo ServicePack               Console WriteLine   Version    0    OSInfo VersionString               Console WriteLine   Bits    0    OSInfo Bits               Console ReadLine

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I need to do this  but I also need to be able as an admin do it remotely  either case this seems to work quite nicely for me       public static bool is64bit String host                using  var reg   RegistryKey OpenRemoteBaseKey RegistryHive LocalMachine  host           using  var key   reg OpenSubKey   Software Microsoft Windows CurrentVersion                           return key GetValue  ProgramFilesDir  x86      null

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UPDATE  As Joel Coehoorn and others suggest  starting at  NET Framework 4 0  you can just check Environment Is64BitOperatingSystem   IntPtr Size won t return the correct value if running in 32-bit  NET Framework 2 0 on 64-bit Windows  it would return 32-bit   As Microsoft s Raymond Chen describes  you have to first check if running in a 64-bit process  I think in  NET you can do so by checking IntPtr Size   and if you are running in a 32-bit process  you still have to call the Win API function IsWow64Process  If this returns true  you are running in a 32-bit process on 64-bit Windows  Microsoft s Raymond Chen  How to detect programmatically whether you are running on 64-bit Windows My solution  static bool is64BitProcess    IntPtr Size    8   static bool is64BitOperatingSystem   is64BitProcess    InternalCheckIsWow64      DllImport  quot kernel32 dll quot   SetLastError   true  CallingConvention   CallingConvention Winapi    return  MarshalAs UnmanagedType Bool   private static extern bool IsWow64Process       In  IntPtr hProcess       Out  out bool wow64Process     public static bool InternalCheckIsWow64         if   Environment OSVersion Version Major    5  amp  amp  Environment OSVersion Version Minor  gt   1             Environment OSVersion Version Major  gt   6                using  Process p   Process GetCurrentProcess                          bool retVal              if   IsWow64Process p Handle  out retVal                                 return false                            return retVal                      else               return false

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I use a version of the following       public static bool Is64BitSystem                 if  Directory Exists Environment GetEnvironmentVariable  Program Files  x86      return true          else return false

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This is just an implementation of what s suggested above by Bruno Lopez  but works on Win2k   all WinXP service packs  Just figured I d post it so other people didn t have roll it by hand   would have posted as a comment  but I m a new user     DllImport  kernel32   SetLastError   true  CallingConvention   CallingConvention Winapi   public extern static IntPtr LoadLibrary string libraryName     DllImport  kernel32   SetLastError   true  CallingConvention   CallingConvention Winapi   public extern static IntPtr GetProcAddress IntPtr hwnd  string procedureName    private delegate bool IsWow64ProcessDelegate  In  IntPtr handle   Out  out bool isWow64Process    public static bool IsOS64Bit         if  IntPtr Size    8     IntPtr Size    4  amp  amp  Is32BitProcessOn64BitProcessor                   return true            else               return false           private static IsWow64ProcessDelegate GetIsWow64ProcessDelegate       IntPtr handle   LoadLibrary  kernel32       if   handle    IntPtr Zero          IntPtr fnPtr   GetProcAddress handle   IsWow64Process         if  fnPtr    IntPtr Zero              return  IsWow64ProcessDelegate Marshal GetDelegateForFunctionPointer  IntPtr fnPtr  typeof IsWow64ProcessDelegate                 return null     private static bool Is32BitProcessOn64BitProcessor       IsWow64ProcessDelegate fnDelegate   GetIsWow64ProcessDelegate       if  fnDelegate    null          return false         bool isWow64    bool retVal   fnDelegate Invoke Process GetCurrentProcess   Handle  out isWow64      if  retVal    false          return false         return isWow64

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foobar  You are right  it is too easy     In 99  of the cases  developers with weak system administrator backgrounds ultimately fail to realize the power Microsoft has always provided for anyone to enumerate Windows   System administrators will always write better and simpler code when it comes to such a point   Nevertheless  one thing to note  build configuration must be AnyCPU for this environment variable to return the correct values on the correct systems   System Environment GetEnvironmentVariable  PROCESSOR ARCHITECTURE     This will return  X86  on 32-bit Windows  and  AMD64  on 64-bit Windows

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All fine  but this should also work from env   PROCESSOR ARCHITECTURE x86       PROCESSOR ARCHITECTURE AMD64   Too easy  maybe  -

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NET 4 has two new properties in the Environment class  Is64BitProcess and Is64BitOperatingSystem  Interestingly  if you use Reflector you can see they are implemented differently in the 32-bit  amp  64-bit versions of mscorlib  The 32-bit version returns false for Is64BitProcess and calls IsWow64Process via P Invoke for Is64BitOperatingSystem  The 64-bit version just returns true for both

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All fine  but this should also work from env   PROCESSOR ARCHITECTURE x86       PROCESSOR ARCHITECTURE AMD64   Too easy  maybe  -

[c#] How to detect Windows 64-bit platform with .NET?

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