Cleaning the Game Files

1. Launch QuickAutoClean from MO2.
2. Select Update.esm.
3. Click the OK button.
   

SSEEdit will now automatically clean the .esm for you. You can close SSEEdit when you see "Quick Clean mode finished" and "Background Loader: finished" at the bottom of the right-hand panel. This could take a while. When it's done, close the SSEEdit window.

Repeat these steps for Dawnguard.esm, Hearthfire.esm and Dragonborn.esm, cleaning one at a time. Do not try to do them all at once. Do not clean Skyrim.esm.

Under no circumstances should you clean mods you add unless you know what you are doing.