Weird error "Unable to copy file ""

I am building a WPF application, I got this weird error :

Unable to copy file "obj\x86\Debug\WPF MVVM Application.exe" to "bin\Debug\WPF MVVM Application.exe". The process cannot access the file 'bin\Debug\WPF MVVM Application.exe' because it is bein开发者_开发技巧g used by another process.

Does anyone have any idea what is wrong? Thanks

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Thanks, it seems like killing the process helps, but it is strange, shouldnt closing the application window kill the process? Thanks

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Hit Ctrl-Alt-Delete and terminate WPF MVVM Application.exe

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If killing WPF Application.exe doesn't help, try to stop devenv.exe process to kill Visual Studio.