It started appearing on my comp a week ago. Microsoft screwed up something during the auto-update.
I tried many things myself, but I failed. So, I had to go to the Technical Communities, where I found a thread on the subject.
Initially, I could only find people who could feel sympathetic but could not help. However, this morning a very bright person (thank you, yeliex!) provided the solution.
The solution is to run these two commands in the Terminal: