This has happened a total of three times, and it's bugging me.
The first time was maybe a month ago, when I attempted to shut down my computer and it said that there were some processes running and that I'd have to "Force Restart." I did so, and when I logged in, my desktop came up looking like I had just installed it, and the little box in the attachment came up.
This has happened two other times recently, but on startup. I'll log in to my account as usual, but instead of "Welcome," it says "Preparing your desktop," and takes forever to load. Then it'll do as I described earlier.
Any idea how to to fix this?