With Visual Studio 2015 I have often the case that following MsBuild exception occurs
warning MSB3026: Could not copy “SomePath/SomeDll.dll” to “SomeOtherPath/SomeDll.dll”. Beginning retry 1 in 1000ms. The process cannot access the file ‘SomePath/SomeDll.dll’ because it is being used by another process.
To get rid of this exception just kill the Visual Studio 2015 Remove Debugger
You can also execute following Command Line command:
taskkill /f /fi "Imagename eq msvsmon.exe"