Visual Studio build fails: unable to copy exe-file

Question

Update: A sample project reproducing this bug can be found here at Microsoft Connect. I have also tested and verified that the solution given in the accepted answer below works on that sample project. If this solution doesn't work for you, you are probably having a different issue (which belongs in a separate question).

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This is a question asked before, both here on Stack Overflow and other places, but none of the suggestions I've found this far has helped me, so I just have to try asking a new question.

Scenario: I have a simple Windows Forms application (C#, .NET 4.0, Visual Studio 2010). It has a couple of base forms that most other forms inherit from, it uses Entity Framework (and POCO classes) for database access. Nothing fancy, no multi-threading or anything.

Problem: All was fine for a while. Then, all out of the blue, Visual Studio failed to build when I was about to launch the application. I got the warning "Unable to delete file '...bin\Debug\[ProjectName].exe'. Access to the path '...bin\Debug\[ProjectName].exe' is denied." and the error "Unable to copy file 'obj\x86\Debug\[ProjectName].exe' to 'bin\Debug\[ProjectName].exe'. The process cannot access the file 'bin\Debug\[ProjectName].exe' because it is being used by another process." (I get both the warning and the error when running Rebuild, but only the error when running Build - don't think that is relevant?)

I understand perfectly fine what the warning and error message says: Visual Studio is obviously trying to overwrite the exe-file while it the same time has a lock on it for some reason. However, this doesn't help me find a solution to the problem... The only thing I've found working is to shut down Visual Studio and start it again. Building and launching then works, untill I make a change in some of the forms, then I have the same problem again and have to restart... Quite frustrating!

As I mentioned above, this seems to be a known problem, so there are lots of suggested solutions. I'll just list what I've already tried here, so people know what to skip:

• Creating a new clean solution and just copy the files from the old solution.

• Adding the following to the following to the project's pre-build event:

  if exist "$(TargetPath).locked" del "$(TargetPath).locked"
     if not exist "$(TargetPath).locked" if exist "$(TargetPath)" move "$(TargetPath)" "$(TargetPath).locked"
  

• Adding the following to the project properties (.csproj file):

  <GenerateResourceNeverLockTypeAssemblies>true</GenerateResourceNeverLockTypeAssemblies>
  

However, none of them worked for me, so you can probably see why I'm starting to get a bit frustrated. I don't know where else to look, so I hope somebody has something to give me! Is this a bug in VS, and if so is there a patch? Or has I done something wrong, do I have a circular reference or similar, and if so how could I find out?

Any suggestions are highly appreciated :)

Update: As mentioned in comment below, I've also checked using Process Explorer that it actually is Visual Studio that is locking the file.

Answer 1

This is rather commonly caused by Avast.

I can usually run my projects in Release regardless, but when running in debug it would pretty regularly fail.

I just add an exclusion for my projects folder and the problem seems to go away. I assume this might also be cause by other antivirus software.

Answer 2

None of the other answers worked for me but closing all open tabs in Visual Studio appears to have solved the problem.

Answer 3

Disable "Enable the Visual Studio hosting process"

Answer 4

I faced the same error.

I solved the problem by deleting all the contents of bin folders of all the dependent projects/libraries.

This error mainly happens due to version changes.

Answer 5

I have found with VS2013 I get this error regularly. Something that seems to work reasonably well is to perform a Rebuild Solution prior trying to run the application. I found that performing a CLEAN sometimes works, but the Rebuild Solution seems to work more consistently.

Answer 6

IF YOUR PROBLEM IS NOT SOLVED YET:

Visual studio's error is :

"The process cannot access the file 'bin\Debug**app.exe**' because it is being used by another process."

So ,go to task manager of windows(Ctrl+Shift+Esc),find your application name and force it to close by Endprocces.