IEnevitable Are you getting the exact error covered in this thread, or a different error, or none at all? If you're not getting this error, please create your own thread describing what happens when you try to play. You can attach a dxdiag to that post. If you are seeing this error, please reply to this thread and provide a dxdiag, as described in the first post.
fraisez Part of the point of a clean uninstall and reinstall is to remove any third-party files, like GShade for example, and one of the fundamental rules of testing is to not add back third-party content until you've tried to use the program (Sims 4 in this case) without it. As to whether you'll keep running into this error, I suppose that depends on whether you keep adding back GShade, and if so, whether GShade starts working with Sims 4 again.
But you shouldn't need to do a complete uninstall. At worst, you can delete the Bin folder inside [install location]\The Sims 4\Game, then run a repair through the EA App (Sims 4 > Manage > Repair) to restore the original files and nothing else.
