Visual Studio locks output file on build

Question

I have a simple WinForms solution in VS 2010. Whenever I build it, output file (bin\debug\app.exe) ends up locked, and subsequent builds fail with a message like "The process cannot access the file 'bin\Debug\app.exe' because it is being used by another process." The only way to build the project is to restart VS after every build, which is very awkward.

I have found this old blog post http://blogs.geekdojo.net/brian/archive/2006/02/17/VS2005FileLocking.aspx - it seems that the problem is really old. Does anyone know what is happening here, or at least some workaround?

Update

I don't actually run the file. Locking happens after build, not after debug (i.e. start VS - build - build - fail!) And I tried turning antivirus off. It doesn't help.

Update 2

Process Explorer shows devenv.exe having loaded the file (in DLLs, not in Handles). It seems like some glitch during build prevented the unloading, but the (first) build completes without any messages other then "1 succeeded, o failed"/

Answer 1

Had the same issue, but found a solution (thanks to Keyvan Nayyeri):

But how to solve this? There are various ways based on your project type but one simple solution that I recommend to Visual Studio add-in developers is to add a simple code to their project's build events.

You can add following lines of code to the pre-build event command line of your project.

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

Answer 2

It is not a virus issue. It is visual studio 2010 bug. It seems the issue is related to using visual studio gui designer.

The workaround here is to move locked output file into another temporary one in pre-build event. It make sense to generate temporary file name randomly.

del "$(TargetPath).locked.*" /q  if exist "$(TargetPath)"  move "$(TargetPath)" "$(TargetPath).locked.%random%" exit /B 0 

In case of using constant temporary file names you will just postpone locks:

That workaround works exactly once

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

I have also found a solution with 2 temporary files that works exactly 2 times.