Hey StevenCowie-
You indicated that you are using UE4.12, if this is accurate please insure that you’re using VS 2015. As JamesSwann95 mentioned, also check the following:
- Add/Remove Programs
- Microsoft Visual Studio 2015 (Change)
- Modify
- Expand Programming Languages / Visual C++
- Check the box for “Common Tools for Visual C++ 2015”
If you are still unable to create a code project after these steps, please try creating a new project in VS (not related to UE4) and compile/build that project. Then try creating a UE4 project.
Cheers