Hey future me, when loading your Unreal solution are you getting the error:

Cannot load project with duplicated project items: MicrosoftGame.Config is included as 'MGCCompile' and as 'MGCCompile' item types.

It means you closed your Visual Studio solution on a special platform which can’t open the solution again. You don’t need to reinstall the SDK! Just change the platform back to Win64 and restart the solution.