Could not copy "obj\Debug\{project}.dll" to "bin\{project}.dll"

Question

Visual Studio Express 2013 for web has been throwing this error a lot lately when I try to run my project, and the only resolution I have found is to quit and relaunch Visual Studio or (sometimes) completely restart Windows. What could cause something like this?

Full Error Dump

Error   19  Could not copy "obj\Debug\HobbsEventsMobile.dll" to "bin\HobbsEventsMobile.dll". Exceeded retry count of 10. Failed.    HobbsEventsMobile
Error   20  Unable to copy file "obj\Debug\HobbsEventsMobile.dll" to "bin\HobbsEventsMobile.dll". The process cannot access the file 'bin\HobbsEventsMobile.dll' because it is being used by another process.   HobbsEventsMobile

Answer 1

Create a pre-build action in your project by going to project properties (right-click on the project in the solution explorer, and select the Properties option), select the Build Events tab. Add this code:

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

https://social.msdn.microsoft.com/Forums/en-US/5b71eb06-5047-483d-8fd3-b75c102d41e9/unable-to-copy-from-objdebug-to-bindebug?forum=Vsexpressinstall&prof=required