Build error The process cannot access the file because it is being used by another process

Question

I ve got a C  webforms app  that until today had been working just swimmingly   Now today  all of a sudden  every time I try run the app  I get a file locking error       Unable to copy file  obj Debug MyProject exe  to  bin Debug MyProject exe   The process cannot access the file  bin Debug MyProject exe  because it is being used by another process    Googling the error doesn t come up with anything beyond the obvious  i e  VS thinks the file is locked   And it is definitely Visual Studio itself that locks the file  because when I close VS and reopen it  the project executes fine - the first time   When I try to run it a second time  I get the file locking error   Closing VS and reopening every time I want to run the app is not a viable workaround   How do I find out what s locking the file  and stop it from getting locked   EDIT  Another interesting discovery  I don t even have to run the app   Just compiling it once causes the file locking  I cannot compile twice in a row   This problem is specific to one project in my solution   All other projects work fine and can be executed as many times as I like   It s only this one project that gets itself locked up

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One more solution  when the files get locked  blocking process is reported  something like  ServiceHub Host CLR x64  7764    with it s id in parentheses   To get rid of the process  open PowerShell  x   Win   I  and type   Stop-Process -Id idNumber

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What worked for me was restarting IIS

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Same error  solved by updating Google Nuget support packages

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I struggled with issue for 5 days and could get the source of the problem through Event Viewer Logs  Port 443  my application trying to access was in use  so I had to change the registry settings   Basically you will b able to reach to source of issue thru error logs in event viewer

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I had two instances of Visual Studio opened the same solution

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Run this command from the Run box   net stop iisadmin  y   and then  iisreset   worked for me  vs 2003

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Deleting Obj  retail and debug folder of the  NET project and re-building again worked for me

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I think most people who answered are a bit clueless and have found a solution by trial and error  I too had this issue recently and looked at the various solutions in this thread and they did not make much sense  I looked in to my project s makefile  it is handmade by my project lead  and I found -j11 in there  I replaced that with -j1 and it fixed the problem  The hunch was that make was probably doing a bad job at running multiple jobs  threads  i e  while one thread was working on a file  another thread was trying to use it  For those who use an IDE to compile your code  you need to look for a build property where you can set the number of jobs and then try compiling your code with the number of jobs set to 1  You might also have to close and restart the IDE  it all depends on how the IDEs are programmed   I understand that this might hinder the performance of your builds but there is probably no alternative to this until either make fixes this bug  if there is one  I haven t bothered to dig in  or the makefile generators become smart enough to prevent this situation

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Recently ran into this problem when attempting to build a solution I am working on  not just a winforms proj   In addition to build failure  I noticed that cleaning projects would quietly fail  checking the bin folder showed that the files had not actually been erased  and closing the Visual Studio did not end the devenv process - rather  it caused it to crash  Windows recovery process would then restart the Visual Studio   After some trial and error  I found the problems only happened to me when I opened the solution from the  Recent  menu on starting up VS  Opening the solution from File  gt  gt  Open  gt  gt  Project Solution found it working as per usually   Currently no idea why - will keep looking into this but for now  at least I can work

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I solved this by deleting the folder bin Debug and  possibly  restarting VS

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Just check the references and remove the self-reference to the project   Explanation  My problem started after creating a custom control and drag and drop it to the toolbox palette for use it in design forms  First appeared a warning saying that there was a redundance between the custom control source file   cs  and the projects executable   exe   On executing debugging appeared the error  unable to access the   exe  because it s being used  and it was true    I literally removed the whole source code regarding the custom control and the problem still remained  until I checked out the references and it was referencing itself in order to be  able to  get the former custom control  I removed the reference and done

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For those who are developing in VS with Docker  restart the docker for windows service and the problem will be solved immediately   Before restarting docker I tried all the mentioned answers  didn t find a msbuild exe process running  also tried restarting VS without avail  only restarting docker worked

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How is your web app configured   Does it run under Cassini  the tray web server  or IIS   This shouldn t happen normally though   I think ProcessExplorer can tell you what files a process has locked   If not process explorer one of the other sysinternals tools   One thing to try before even downloading one of the SI tools is to stop the Cassini web server  and seeing if that frees up the file

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I had faced the same issue   I tried Several Solutions listed above but they didn t work for me    I solved this issue by Closing the Connection from the Server Explorer and closed all the Tabs which was open in the Visual Studio

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Little late to answer  but I solved this by going to the properties of the project  gt  tab  quot Debug quot   gt  unchecked  quot Enable the Visual Studio hosting process quot  option

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If this is an SSIS project  then open task manager and kill all instances of DtsDebugHost exe  that should release the locked files

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I have found a simple solution which works for me  It goes like this   When the problem occurs  just change the building configuration at the top  if in    Release    to    Debug    and vice versa   build and then change back to previous configuration and build again     I suppose that changing the configuration releases the vcshost and devenv

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In my case there were some vstest processes running  with various names but all containing the string vstest   I had to terminate them in taskmgr

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i had this same problem as well  changing the debug release config didn t do the trick  at least not without building in between   in my solution  winform  it was solved by opening the mainform of the winform in the designer  switching to code  F7   Then closing the code  closing the designer of the winform and rebuild all  ctrl-shift-B   This worked for me   seems like some kind of handle from within the winform app  which runs a backgroundworker  still had a file handle on some of the other libraries used

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I had the same issue and could not rectify by using any of the methods mentioned in previous answers  I resolved the issue by killing all instances of  SSIS Debug Hist  32 bit   in task manager and now working as normal

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I had the same issue on my Xamarin application in visual studio and it was resolved by unplugging my test mobile device  The application was closed and the debugger was stopped but the error was still happening when trying to build or rebuild the solution  It only stopped after i unplugged the device because i had to receive a call

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Well  I solved the problem myself - though I still have no clue why   I decided to isolate the problem by removing all files from the project  then re-adding them and determining that way which file was the source of my trouble   So  one by one I reintroduced files to the project  compiled  amp  cleaned each step of the way    until    I added the last one         and everything still worked fine   I did a compare to the source control of my original  csproj  no real differences   And even when I tried reverting to the previous version of the  csproj  it still worked   Black magic   If it works  sometimes it s better not to ask why - just accept it and move on     EDIT  The problem is a recurring one  and I believe I ve isolated it to when I have the form designer open of an abstract generic form at compile time     Lesson learned  Make sure the Form Designer of any abstract or generic forms or controls is closed before you compile   If not  you have to close VS and reopen

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I had a similar error but during the deployment of the UWP application  Finally  I found out the process that used a file that caused this error and stopped it  Credits to this link  Copy-pasted version is below  How to Solve the Issue  One of the easiest ways to handle locked files or folders is to use Microsoft Sysinternals Process Explorer  Identify what program is using a file Using Process Explorer there is a simple way to find the program   Open Process Explorer  running as administrator   On the toolbar  find the gunsight icon on the right  Drag the icon and drop it on the open file or folder that is locked  The executable that is using the file will be highlighted in the Process Explorer main display list   Identify which handle or DLL is using a file  Open Process Explorer  running as administrator   Enter the keyboard shortcut Ctrl F  Alternatively  click the    Find    menu and select    Find a Handle or DLL     A search dialog box will open  Type in the name of the locked file or other file of interest  Partial names are usually sufficient  Click the button    Search     A list will be generated  There may be a number of entries   And then kill this process

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I recently ran into the issue when deploying to Service Fabric  The error is implying a  file  is in use  however  I found that the port was being used by another IDE  By stopping a running service which was already hosting on the port  I was able to stop this exception from occurring

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I have overcome this problem by renaming the locked file  using Windows Explorer   I was not allowed to delete the file  but renaming the locked file works

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I had this issue  and its an issue I have seen in other places not just VS    It s caused by Dropbox  in my case   After editing some code and hitting run  sometimes dropbox immediately locks the file  so it can process it    Solution 1  Just hit run again  Solution 2  Pause dropbox   not good if your using dropbox as your cloud backup   Solution 3  Remove the build folder from dropboxes sync list

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What we have discovered here  is the following  In the project properties page  Debug tab  uncheck the  Enable visual studio hosting process    I am unsure what this  property is for  but it does the work once unchecked

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Actually you should want  Enable the Visual Studio hosting process  checked  At least for VS2010 anyway  And I also have   if exist    TargetPath  locked  del    TargetPath  locked  if exist    TargetPath   if not exist    TargetPath  locked  move    TargetPath      TargetPath  locked   in the pre-build options  This problem has dogged me for a very long time and it wasn t until John W  mentioned this check box that I even took notice that it existed and low and behold it was already unchecked   Also notice that -app-vshost exe runs in the background even when not debugging  Which is what makes it successfully build and run every time I guess  It wasn t running before  And I also tried cleaning out the debug and release folders and changing the target type constantly and nothing worked except as described above  My solution before was to just wait 5 minutes between builds  which got super annoying and time-consuming to get anything done  I haven t seen any change in behavior where it mattered what tabs where open or XNA vs windows form or designers being opened  This issue occurred in 32-bit or 64-bit builds and didn t matter if I killed an app with ALT-F4 or killing it with task manager  which would  in theory  not allow the app to close or release resources  At first I thought it was a garbage collection issue

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VS2017 - Solved by closing all instances of MSBuild exe in the windows task manager

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I use Visual Studio Code and I received this error because the dev server was running  I ran the dev server by pressing Ctrl   F5     Thus  I just clicked on the stop sign to stop it and the error went away

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For me  it was a Windows Service that was installed and running   Once I stopped it  the build was successful

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Just to throw in my 2 cents  My issue was solved by opening Task Manager and killing the application  It was running in the background without any indication that it was running at all  no item in the task bar  no ui  nothing   but I am not sure why this happened  Obviously the debugger was not running and I only had a single instance of VS opened at the time  It amazes me that this is still happening in this VS 2017    Perhaps I can add a build step that looks for the application running the background and kills it before starting the new one

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When I ended the process  Net Core Host  everything built fine  I didn t have to close Visual Studio or do change anything else

[c#] Build error: "The process cannot access the file because it is being used by another process"

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