This is the error i get when trying to copy the project to a new verion:
Project files could not be generated. Log output:
Running C:/Program Files (x86)/Epic Games/4.10/Engine/Binaries/DotNET/UnrealBuildTool.exe -projectfiles -project=“C:/Users/Gunnar/Documents/Unreal Projects/Paintball 4.10/Paintball.uproject” -game -rocket -progress -2015
Visual C++ 2015 toolchain does not appear to be correctly installed. Please verify that “Common Tools for Visual C++ 2015” was selected when installing Visual Studio 2015.
Discovering modules, targets and source code for game…
UnrealBuildTool Exception: ERROR: Windows SDK v8.1 must be installed in order to build this target.
If you re-run the install for VS2015 it should prompt you to “Repair” “Modify” or “Uninstall”. If you select modify there should be a checkbox and a drop-down for “Programming Languages”. Inside the drop-down there is another checkbox/drop-down for C++. Inside the second drop-down you should find “Common Tools for Visual C++ 2015”. You can select the checkbox for C++ itself which will automatically add the “Common Tools…” as well. After this you should be able to update VS and continue working with code in UE4.