VS "Could not copy" error

Trying to build to WSA 10 from VS2015 (Unity 5.2f3) and roughly half the time I'm receiving the following error when trying to build to device:

Code (CSharp):

1. 3>C:\projects\code\Unity\WSATest\Build\WSATest\WSATest.csproj(235,5): error MSB3027: Could not copy "C:\projects\code\Unity\WSATest\bin\UWP\ARM\Debug\Unprocessed\Assembly-CSharp.dll" to "C:\projects\code\Unity\WSATest\bin\UWP\ARM\Debug\Assembly-CSharp.dll". Exceeded retry count of 10. Failed.
2. 3>C:\projects\code\Unity\WSATest\Build\WSATest\WSATest.csproj(235,5): error MSB3021: Unable to copy file "C:\projects\code\Unity\WSATest\bin\UWP\ARM\Debug\Unprocessed\Assembly-CSharp.dll" to "C:\projects\code\Unity\WSATest\bin\UWP\ARM\Debug\Assembly-CSharp.dll". The requested operation cannot be performed on a file with a user-mapped section open.
3. 3>C:\projects\code\Unity\WSATest\Build\WSATest\WSATest.csproj(235,5): error MSB3021:

It seems to have to do with possibly having the build folder open in Explorer recently? If I close the folder and wait a bit then the error usually (but not always) goes away. Wondering if it also has to do with the project being on the C:\ and Windows 10 having issues with writing/permissions on C?

 

Thanks for the quick response. So if I uncheck that, does that mean it won't generate the needed *.csproj files for WSA or what exactly is that doing?