title: UE4 - Visual Studio cannot open any source file after I add new c++ files from Editor - UBT_COMPILED_PLATFORM error
body: <p>I started a c++ project in UE4.25 days ago, and started prototyping in blueprints.
  Now I wanted to start and take my logic to c++.</p>
  
  <p><strong>Problem:</strong> As soon as I created a new Actor from the Editor (right-click -> new c++), the new file generated <em>thousands</em> of errors engine-related, and could not find source files anymore. It could compile, but then I couldn't work on it, because it was full of squiggly lines and I couldn't get IntelliSense to work even on basic types as FVectors.</p>
  
  <p><strong>What I tried:</strong> I tried manually adding UE paths to the project settings; I tried deleting and changing the Actor's name; Rebuilt every time.
  Uninstalling and reinstalling UE4.25 actually changed something: There were now just 10 errors instead of 10000, and they all were about <strong>missing source files</strong> (starting from CoreMinimal.h).
  I tried again with every solution I found on the internet because why not, but no luck.</p>
  
  <p>I am now uninstalling and reinstalling Visual Studio as well. Has anyone encountered this kind of error? Is there any new solution?</p>
  
  <p><strong>EDIT:</strong> Reinstalling Visual Studio didn't help. I get errors about 'cannot open source file' UBT_COMPILED_PLATFORM/UBT_COMPILED_PLATFORM CriticalSection.h" PlatformCompilerPreSetup.h" PlatformCompilerSetup.h" PlatformAtomics.h" PlatformMath.h" PlatformMemory.h" PlatformMisc.h" PlatformProcess.h" PlatformProperties.h" PlatformString.h" PlatformTime.h" PlatformTLS.h and then 13345 other errors not about includes.</p>