So I went to turn on my 722 last night after having been out for the evening. It started acting strangely, and basically wouldn't turn on at all. Black screen.
So I rebooted it, and then it came up with an Error 061 and some text about it downloading software, it could take 20 min, don't disturb it. So I didn't. Approx 20 min later, then message 303 showed up, that it was loading stuff into memory, don't disturb it, so I didn't. That didn't take too long, in the mean time I was researching those error codes, and basically there's not a lot of info out there, but the gist was: your hard drive might be toast.
Anyway, it finished, my old recordings were still there, all my timers were fine, nothing seemed changed at all. In fact, the previous search stuff was still listed when I went to search for something new.
I very quickly moved any recordings I had that I didn't want to lose, to an external hard drive.
Looks like it somehow spotted something wrong with the system software, downloaded and installed it again, and it looks OK. For now I suppose.