[MissingWebPart] WebPart class [8d6034c4-a416-e535-281a-6b714894e1aa] is referenced  times.
[MissingWebPart] WebPart class [baf5274e-a800-8dc3-96d0-0003d9405663] is referenced  times in the database
It’s true: simply go to the following URLs on your server:
Then run iisreset. I had to do it a couple times before it worked, but it’s probably that I didn’t wait long enough.