How do I find out which process is locking a file using NET

Question

I ve seen several of answers about using Handle or Process Monitor  but I would like to be able to find out in my own code  C   which process is locking a file  I have a nasty feeling that I m going to have to spelunk around in the win32 API  but if anyone has already done this and can put me on the right track  I d really appreciate the help  Update Links to similar questions  How does one figure out what process locked a file using c   Command line tool Across a Network Locking a USB device Unit test fails with locked file deleting locked file

User · Answer

Long ago it was impossible to reliably get the list of processes locking a file because Windows simply did not track that information. To support the Restart Manager API, that information is now tracked.

I put together code that takes the path of a file and returns a List<Process> of all processes that are locking that file.

using System.Runtime.InteropServices;
using System.Diagnostics;
using System;
using System.Collections.Generic;

static public class FileUtil
{
    [StructLayout(LayoutKind.Sequential)]
    struct RM_UNIQUE_PROCESS
    {
        public int dwProcessId;
        public System.Runtime.InteropServices.ComTypes.FILETIME ProcessStartTime;
    }

    const int RmRebootReasonNone = 0;
    const int CCH_RM_MAX_APP_NAME = 255;
    const int CCH_RM_MAX_SVC_NAME = 63;

    enum RM_APP_TYPE
    {
        RmUnknownApp = 0,
        RmMainWindow = 1,
        RmOtherWindow = 2,
        RmService = 3,
        RmExplorer = 4,
        RmConsole = 5,
        RmCritical = 1000
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    struct RM_PROCESS_INFO
    {
        public RM_UNIQUE_PROCESS Process;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_APP_NAME + 1)]
        public string strAppName;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_SVC_NAME + 1)]
        public string strServiceShortName;

        public RM_APP_TYPE ApplicationType;
        public uint AppStatus;
        public uint TSSessionId;
        [MarshalAs(UnmanagedType.Bool)]
        public bool bRestartable;
    }

    [DllImport("rstrtmgr.dll", CharSet = CharSet.Unicode)]
    static extern int RmRegisterResources(uint pSessionHandle,
                                          UInt32 nFiles,
                                          string[] rgsFilenames,
                                          UInt32 nApplications,
                                          [In] RM_UNIQUE_PROCESS[] rgApplications,
                                          UInt32 nServices,
                                          string[] rgsServiceNames);

    [DllImport("rstrtmgr.dll", CharSet = CharSet.Auto)]
    static extern int RmStartSession(out uint pSessionHandle, int dwSessionFlags, string strSessionKey);

    [DllImport("rstrtmgr.dll")]
    static extern int RmEndSession(uint pSessionHandle);

    [DllImport("rstrtmgr.dll")]
    static extern int RmGetList(uint dwSessionHandle,
                                out uint pnProcInfoNeeded,
                                ref uint pnProcInfo,
                                [In, Out] RM_PROCESS_INFO[] rgAffectedApps,
                                ref uint lpdwRebootReasons);

    /// <summary>
    /// Find out what process(es) have a lock on the specified file.
    /// </summary>
    /// <param name="path">Path of the file.</param>
    /// <returns>Processes locking the file</returns>
    /// <remarks>See also:
    /// http://msdn.microsoft.com/en-us/library/windows/desktop/aa373661(v=vs.85).aspx
    /// http://wyupdate.googlecode.com/svn-history/r401/trunk/frmFilesInUse.cs (no copyright in code at time of viewing)
    /// 
    /// </remarks>
    static public List<Process> WhoIsLocking(string path)
    {
        uint handle;
        string key = Guid.NewGuid().ToString();
        List<Process> processes = new List<Process>();

        int res = RmStartSession(out handle, 0, key);
        if (res != 0) throw new Exception("Could not begin restart session.  Unable to determine file locker.");

        try
        {
            const int ERROR_MORE_DATA = 234;
            uint pnProcInfoNeeded = 0,
                 pnProcInfo = 0,
                 lpdwRebootReasons = RmRebootReasonNone;

            string[] resources = new string[] { path }; // Just checking on one resource.

            res = RmRegisterResources(handle, (uint)resources.Length, resources, 0, null, 0, null);

            if (res != 0) throw new Exception("Could not register resource.");                                    

            //Note: there's a race condition here -- the first call to RmGetList() returns
            //      the total number of process. However, when we call RmGetList() again to get
            //      the actual processes this number may have increased.
            res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, null, ref lpdwRebootReasons);

            if (res == ERROR_MORE_DATA)
            {
                // Create an array to store the process results
                RM_PROCESS_INFO[] processInfo = new RM_PROCESS_INFO[pnProcInfoNeeded];
                pnProcInfo = pnProcInfoNeeded;

                // Get the list
                res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, processInfo, ref lpdwRebootReasons);
                if (res == 0)
                {
                    processes = new List<Process>((int)pnProcInfo);

                    // Enumerate all of the results and add them to the 
                    // list to be returned
                    for (int i = 0; i < pnProcInfo; i++)
                    {
                        try
                        {
                            processes.Add(Process.GetProcessById(processInfo[i].Process.dwProcessId));
                        }
                        // catch the error -- in case the process is no longer running
                        catch (ArgumentException) { }
                    }
                }
                else throw new Exception("Could not list processes locking resource.");                    
            }
            else if (res != 0) throw new Exception("Could not list processes locking resource. Failed to get size of result.");                    
        }
        finally
        {
            RmEndSession(handle);
        }

        return processes;
    }
}

Using from Limited Permission (e.g. IIS)

This call accesses the registry. If the process does not have permission to do so, you will get ERROR_WRITE_FAULT, meaning An operation was unable to read or write to the registry. You could selectively grant permission to your restricted account to the necessary part of the registry. It is more secure though to have your limited access process set a flag (e.g. in the database or the file system, or by using an interprocess communication mechanism such as queue or named pipe) and have a second process call the Restart Manager API.

Granting other-than-minimal permissions to the IIS user is a security risk.

User · Answer

simpler with linq   public void KillProcessesAssociatedToFile string file                GetProcessesAssociatedToFile file  ForEach x   gt                        x Kill                x WaitForExit 10000                          public List lt Process gt  GetProcessesAssociatedToFile string file                return Process GetProcesses                Where x   gt   x HasExited                  amp  amp  x Modules Cast lt ProcessModule gt    ToList                        Exists y   gt  y FileName ToLowerInvariant      file ToLowerInvariant                      ToList

User · Answer

This works for DLLs locked by other processes  This routine will not find out for example that a text file is locked by a word process     C    using System Management   using System IO      static class Module1     static internal ArrayList myProcessArray   new ArrayList     private static Process myProcess    public static void Main            string strFile    c   windows  system32  msi dll        ArrayList a   getFileProcesses strFile        foreach  Process p in a             Debug Print p ProcessName                private static ArrayList getFileProcesses string strFile          myProcessArray Clear         Process   processes   Process GetProcesses       int i   0       for  i   0  i  lt   processes GetUpperBound 0  - 1  i               myProcess   processes i            if   myProcess HasExited                 try                    ProcessModuleCollection modules   myProcess Modules                   int j   0                   for  j   0  j  lt   modules Count - 1  j                           if   modules Item j  FileName ToLower CompareTo strFile ToLower     0                              myProcessArray Add myProcess                            break     TODO  might not be correct  Was   Exit For                                                                       catch  Exception exception                                  MsgBox   Error      amp  exception Message                          return myProcessArray           VB Net   Imports System Management Imports System IO  Module Module1 Friend myProcessArray As New ArrayList Private myProcess As Process  Sub Main        Dim strFile As String    c  windows system32 msi dll      Dim a As ArrayList   getFileProcesses strFile      For Each p As Process In a         Debug Print p ProcessName      Next End Sub   Private Function getFileProcesses ByVal strFile As String  As ArrayList     myProcessArray Clear       Dim processes As Process     Process GetProcesses     Dim i As Integer     For i   0 To processes GetUpperBound 0  - 1         myProcess   processes i          If Not myProcess HasExited Then             Try                 Dim modules As ProcessModuleCollection   myProcess Modules                 Dim j As Integer                 For j   0 To modules Count - 1                     If  modules Item j  FileName ToLower CompareTo strFile ToLower    0  Then                         myProcessArray Add myProcess                          Exit For                     End If                 Next j             Catch exception As Exception                  MsgBox   Error      amp  exception Message               End Try         End If     Next i     Return myProcessArray End Function End Module

User · Answer

It is very complex to invoke Win32 from C    You should use the tool Handle exe   After that your C  code have to be the following   string fileName     c  aaa doc    Path to locked file  Process tool   new Process    tool StartInfo FileName    handle exe   tool StartInfo Arguments   fileName    accepteula   tool StartInfo UseShellExecute   false  tool StartInfo RedirectStandardOutput   true  tool Start               tool WaitForExit    string outputTool   tool StandardOutput ReadToEnd     string matchPattern        lt   s pid  s   b  d   b    s     foreach Match match in Regex Matches outputTool  matchPattern         Process GetProcessById int Parse match Value   Kill

User · Answer

This works for DLLs locked by other processes  This routine will not find out for example that a text file is locked by a word process     C    using System Management   using System IO      static class Module1     static internal ArrayList myProcessArray   new ArrayList     private static Process myProcess    public static void Main            string strFile    c   windows  system32  msi dll        ArrayList a   getFileProcesses strFile        foreach  Process p in a             Debug Print p ProcessName                private static ArrayList getFileProcesses string strFile          myProcessArray Clear         Process   processes   Process GetProcesses       int i   0       for  i   0  i  lt   processes GetUpperBound 0  - 1  i               myProcess   processes i            if   myProcess HasExited                 try                    ProcessModuleCollection modules   myProcess Modules                   int j   0                   for  j   0  j  lt   modules Count - 1  j                           if   modules Item j  FileName ToLower CompareTo strFile ToLower     0                              myProcessArray Add myProcess                            break     TODO  might not be correct  Was   Exit For                                                                       catch  Exception exception                                  MsgBox   Error      amp  exception Message                          return myProcessArray           VB Net   Imports System Management Imports System IO  Module Module1 Friend myProcessArray As New ArrayList Private myProcess As Process  Sub Main        Dim strFile As String    c  windows system32 msi dll      Dim a As ArrayList   getFileProcesses strFile      For Each p As Process In a         Debug Print p ProcessName      Next End Sub   Private Function getFileProcesses ByVal strFile As String  As ArrayList     myProcessArray Clear       Dim processes As Process     Process GetProcesses     Dim i As Integer     For i   0 To processes GetUpperBound 0  - 1         myProcess   processes i          If Not myProcess HasExited Then             Try                 Dim modules As ProcessModuleCollection   myProcess Modules                 Dim j As Integer                 For j   0 To modules Count - 1                     If  modules Item j  FileName ToLower CompareTo strFile ToLower    0  Then                         myProcessArray Add myProcess                          Exit For                     End If                 Next j             Catch exception As Exception                  MsgBox   Error      amp  exception Message               End Try         End If     Next i     Return myProcessArray End Function End Module

User · Answer

It is very complex to invoke Win32 from C    You should use the tool Handle exe   After that your C  code have to be the following   string fileName     c  aaa doc    Path to locked file  Process tool   new Process    tool StartInfo FileName    handle exe   tool StartInfo Arguments   fileName    accepteula   tool StartInfo UseShellExecute   false  tool StartInfo RedirectStandardOutput   true  tool Start               tool WaitForExit    string outputTool   tool StandardOutput ReadToEnd     string matchPattern        lt   s pid  s   b  d   b    s     foreach Match match in Regex Matches outputTool  matchPattern         Process GetProcessById int Parse match Value   Kill

User · Answer

I had issues with stefan s solution   Below is a modified version which seems to work well   using System  using System Collections  using System Diagnostics  using System Management  using System IO   static class Module1       static internal ArrayList myProcessArray   new ArrayList        private static Process myProcess       public static void Main                 string strFile    c   windows  system32  msi dll           ArrayList a   getFileProcesses strFile           foreach  Process p in a                        Debug Print p ProcessName                        private static ArrayList getFileProcesses string strFile                myProcessArray Clear            Process   processes   Process GetProcesses            int i   0          for  i   0  i  lt   processes GetUpperBound 0  - 1  i                          myProcess   processes i                 if   myProcess HasExited    This will cause an  Access is denied  error             if  myProcess Threads Count  gt  0                                try                                       ProcessModuleCollection modules   myProcess Modules                      int j   0                      for  j   0  j  lt   modules Count - 1  j                                                  if   modules j  FileName ToLower   CompareTo strFile ToLower       0                                                         myProcessArray Add myProcess                               break                                 TODO  might not be correct  Was   Exit For                                                                                   catch  Exception exception                                          MsgBox   Error      amp  exception Message                                                       return myProcessArray            UPDATE  If you just want to know which process es  are locking a particular DLL  you can execute and parse the output of tasklist  m YourDllName dll  Works on Windows XP and later   See  What does this do  tasklist  m  quot mscor  quot

User · Answer

One of the good things about handle exe is that you can run it as a subprocess and parse the output   We do this in our deployment script - works like a charm

User · Answer

I had issues with stefan s solution   Below is a modified version which seems to work well   using System  using System Collections  using System Diagnostics  using System Management  using System IO   static class Module1       static internal ArrayList myProcessArray   new ArrayList        private static Process myProcess       public static void Main                 string strFile    c   windows  system32  msi dll           ArrayList a   getFileProcesses strFile           foreach  Process p in a                        Debug Print p ProcessName                        private static ArrayList getFileProcesses string strFile                myProcessArray Clear            Process   processes   Process GetProcesses            int i   0          for  i   0  i  lt   processes GetUpperBound 0  - 1  i                          myProcess   processes i                 if   myProcess HasExited    This will cause an  Access is denied  error             if  myProcess Threads Count  gt  0                                try                                       ProcessModuleCollection modules   myProcess Modules                      int j   0                      for  j   0  j  lt   modules Count - 1  j                                                  if   modules j  FileName ToLower   CompareTo strFile ToLower       0                                                         myProcessArray Add myProcess                               break                                 TODO  might not be correct  Was   Exit For                                                                                   catch  Exception exception                                          MsgBox   Error      amp  exception Message                                                       return myProcessArray            UPDATE  If you just want to know which process es  are locking a particular DLL  you can execute and parse the output of tasklist  m YourDllName dll  Works on Windows XP and later   See  What does this do  tasklist  m  quot mscor  quot

User · Answer

This works for DLLs locked by other processes  This routine will not find out for example that a text file is locked by a word process     C    using System Management   using System IO      static class Module1     static internal ArrayList myProcessArray   new ArrayList     private static Process myProcess    public static void Main            string strFile    c   windows  system32  msi dll        ArrayList a   getFileProcesses strFile        foreach  Process p in a             Debug Print p ProcessName                private static ArrayList getFileProcesses string strFile          myProcessArray Clear         Process   processes   Process GetProcesses       int i   0       for  i   0  i  lt   processes GetUpperBound 0  - 1  i               myProcess   processes i            if   myProcess HasExited                 try                    ProcessModuleCollection modules   myProcess Modules                   int j   0                   for  j   0  j  lt   modules Count - 1  j                           if   modules Item j  FileName ToLower CompareTo strFile ToLower     0                              myProcessArray Add myProcess                            break     TODO  might not be correct  Was   Exit For                                                                       catch  Exception exception                                  MsgBox   Error      amp  exception Message                          return myProcessArray           VB Net   Imports System Management Imports System IO  Module Module1 Friend myProcessArray As New ArrayList Private myProcess As Process  Sub Main        Dim strFile As String    c  windows system32 msi dll      Dim a As ArrayList   getFileProcesses strFile      For Each p As Process In a         Debug Print p ProcessName      Next End Sub   Private Function getFileProcesses ByVal strFile As String  As ArrayList     myProcessArray Clear       Dim processes As Process     Process GetProcesses     Dim i As Integer     For i   0 To processes GetUpperBound 0  - 1         myProcess   processes i          If Not myProcess HasExited Then             Try                 Dim modules As ProcessModuleCollection   myProcess Modules                 Dim j As Integer                 For j   0 To modules Count - 1                     If  modules Item j  FileName ToLower CompareTo strFile ToLower    0  Then                         myProcessArray Add myProcess                          Exit For                     End If                 Next j             Catch exception As Exception                  MsgBox   Error      amp  exception Message               End Try         End If     Next i     Return myProcessArray End Function End Module

User · Answer

This works for DLLs locked by other processes  This routine will not find out for example that a text file is locked by a word process     C    using System Management   using System IO      static class Module1     static internal ArrayList myProcessArray   new ArrayList     private static Process myProcess    public static void Main            string strFile    c   windows  system32  msi dll        ArrayList a   getFileProcesses strFile        foreach  Process p in a             Debug Print p ProcessName                private static ArrayList getFileProcesses string strFile          myProcessArray Clear         Process   processes   Process GetProcesses       int i   0       for  i   0  i  lt   processes GetUpperBound 0  - 1  i               myProcess   processes i            if   myProcess HasExited                 try                    ProcessModuleCollection modules   myProcess Modules                   int j   0                   for  j   0  j  lt   modules Count - 1  j                           if   modules Item j  FileName ToLower CompareTo strFile ToLower     0                              myProcessArray Add myProcess                            break     TODO  might not be correct  Was   Exit For                                                                       catch  Exception exception                                  MsgBox   Error      amp  exception Message                          return myProcessArray           VB Net   Imports System Management Imports System IO  Module Module1 Friend myProcessArray As New ArrayList Private myProcess As Process  Sub Main        Dim strFile As String    c  windows system32 msi dll      Dim a As ArrayList   getFileProcesses strFile      For Each p As Process In a         Debug Print p ProcessName      Next End Sub   Private Function getFileProcesses ByVal strFile As String  As ArrayList     myProcessArray Clear       Dim processes As Process     Process GetProcesses     Dim i As Integer     For i   0 To processes GetUpperBound 0  - 1         myProcess   processes i          If Not myProcess HasExited Then             Try                 Dim modules As ProcessModuleCollection   myProcess Modules                 Dim j As Integer                 For j   0 To modules Count - 1                     If  modules Item j  FileName ToLower CompareTo strFile ToLower    0  Then                         myProcessArray Add myProcess                          Exit For                     End If                 Next j             Catch exception As Exception                  MsgBox   Error      amp  exception Message               End Try         End If     Next i     Return myProcessArray End Function End Module

User · Answer

One of the good things about handle exe is that you can run it as a subprocess and parse the output   We do this in our deployment script - works like a charm

User · Answer

One of the good things about handle exe is that you can run it as a subprocess and parse the output   We do this in our deployment script - works like a charm

User · Answer

One of the good things about handle exe is that you can run it as a subprocess and parse the output   We do this in our deployment script - works like a charm

User · Answer

simpler with linq   public void KillProcessesAssociatedToFile string file                GetProcessesAssociatedToFile file  ForEach x   gt                        x Kill                x WaitForExit 10000                          public List lt Process gt  GetProcessesAssociatedToFile string file                return Process GetProcesses                Where x   gt   x HasExited                  amp  amp  x Modules Cast lt ProcessModule gt    ToList                        Exists y   gt  y FileName ToLowerInvariant      file ToLowerInvariant                      ToList

User · Answer

Long ago it was impossible to reliably get the list of processes locking a file because Windows simply did not track that information. To support the Restart Manager API, that information is now tracked.

I put together code that takes the path of a file and returns a List<Process> of all processes that are locking that file.

using System.Runtime.InteropServices;
using System.Diagnostics;
using System;
using System.Collections.Generic;

static public class FileUtil
{
    [StructLayout(LayoutKind.Sequential)]
    struct RM_UNIQUE_PROCESS
    {
        public int dwProcessId;
        public System.Runtime.InteropServices.ComTypes.FILETIME ProcessStartTime;
    }

    const int RmRebootReasonNone = 0;
    const int CCH_RM_MAX_APP_NAME = 255;
    const int CCH_RM_MAX_SVC_NAME = 63;

    enum RM_APP_TYPE
    {
        RmUnknownApp = 0,
        RmMainWindow = 1,
        RmOtherWindow = 2,
        RmService = 3,
        RmExplorer = 4,
        RmConsole = 5,
        RmCritical = 1000
    }

    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
    struct RM_PROCESS_INFO
    {
        public RM_UNIQUE_PROCESS Process;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_APP_NAME + 1)]
        public string strAppName;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCH_RM_MAX_SVC_NAME + 1)]
        public string strServiceShortName;

        public RM_APP_TYPE ApplicationType;
        public uint AppStatus;
        public uint TSSessionId;
        [MarshalAs(UnmanagedType.Bool)]
        public bool bRestartable;
    }

    [DllImport("rstrtmgr.dll", CharSet = CharSet.Unicode)]
    static extern int RmRegisterResources(uint pSessionHandle,
                                          UInt32 nFiles,
                                          string[] rgsFilenames,
                                          UInt32 nApplications,
                                          [In] RM_UNIQUE_PROCESS[] rgApplications,
                                          UInt32 nServices,
                                          string[] rgsServiceNames);

    [DllImport("rstrtmgr.dll", CharSet = CharSet.Auto)]
    static extern int RmStartSession(out uint pSessionHandle, int dwSessionFlags, string strSessionKey);

    [DllImport("rstrtmgr.dll")]
    static extern int RmEndSession(uint pSessionHandle);

    [DllImport("rstrtmgr.dll")]
    static extern int RmGetList(uint dwSessionHandle,
                                out uint pnProcInfoNeeded,
                                ref uint pnProcInfo,
                                [In, Out] RM_PROCESS_INFO[] rgAffectedApps,
                                ref uint lpdwRebootReasons);

    /// <summary>
    /// Find out what process(es) have a lock on the specified file.
    /// </summary>
    /// <param name="path">Path of the file.</param>
    /// <returns>Processes locking the file</returns>
    /// <remarks>See also:
    /// http://msdn.microsoft.com/en-us/library/windows/desktop/aa373661(v=vs.85).aspx
    /// http://wyupdate.googlecode.com/svn-history/r401/trunk/frmFilesInUse.cs (no copyright in code at time of viewing)
    /// 
    /// </remarks>
    static public List<Process> WhoIsLocking(string path)
    {
        uint handle;
        string key = Guid.NewGuid().ToString();
        List<Process> processes = new List<Process>();

        int res = RmStartSession(out handle, 0, key);
        if (res != 0) throw new Exception("Could not begin restart session.  Unable to determine file locker.");

        try
        {
            const int ERROR_MORE_DATA = 234;
            uint pnProcInfoNeeded = 0,
                 pnProcInfo = 0,
                 lpdwRebootReasons = RmRebootReasonNone;

            string[] resources = new string[] { path }; // Just checking on one resource.

            res = RmRegisterResources(handle, (uint)resources.Length, resources, 0, null, 0, null);

            if (res != 0) throw new Exception("Could not register resource.");                                    

            //Note: there's a race condition here -- the first call to RmGetList() returns
            //      the total number of process. However, when we call RmGetList() again to get
            //      the actual processes this number may have increased.
            res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, null, ref lpdwRebootReasons);

            if (res == ERROR_MORE_DATA)
            {
                // Create an array to store the process results
                RM_PROCESS_INFO[] processInfo = new RM_PROCESS_INFO[pnProcInfoNeeded];
                pnProcInfo = pnProcInfoNeeded;

                // Get the list
                res = RmGetList(handle, out pnProcInfoNeeded, ref pnProcInfo, processInfo, ref lpdwRebootReasons);
                if (res == 0)
                {
                    processes = new List<Process>((int)pnProcInfo);

                    // Enumerate all of the results and add them to the 
                    // list to be returned
                    for (int i = 0; i < pnProcInfo; i++)
                    {
                        try
                        {
                            processes.Add(Process.GetProcessById(processInfo[i].Process.dwProcessId));
                        }
                        // catch the error -- in case the process is no longer running
                        catch (ArgumentException) { }
                    }
                }
                else throw new Exception("Could not list processes locking resource.");                    
            }
            else if (res != 0) throw new Exception("Could not list processes locking resource. Failed to get size of result.");                    
        }
        finally
        {
            RmEndSession(handle);
        }

        return processes;
    }
}

Using from Limited Permission (e.g. IIS)

This call accesses the registry. If the process does not have permission to do so, you will get ERROR_WRITE_FAULT, meaning An operation was unable to read or write to the registry. You could selectively grant permission to your restricted account to the necessary part of the registry. It is more secure though to have your limited access process set a flag (e.g. in the database or the file system, or by using an interprocess communication mechanism such as queue or named pipe) and have a second process call the Restart Manager API.

Granting other-than-minimal permissions to the IIS user is a security risk.

[c#] How do I find out which process is locking a file using .NET?

Examples related to c#

Examples related to file-locking