I have been working on building a map for about a month, and now, for some weird reason, its not letting me open the project up.
When I press “Yes” it will try to rebuild the map, but then this comes up
I am not using a different game version, I had just opened the project up yesterday! If i cant fix this, im gonna switch back to Unity XD
Try to delete Intermediate, Saved, Build and Binaries folders in Project root.
It is like to cached data error.
First did you check to see if you had updated your engine?
Second is it a C++ or BP project?
If it is a C++ project try going into the solution explorer and delete the SLN folder.
Then right click on the Uproject and hit generate source files.
Then open the sln and hit the play button (Rebuild from source)