system
9
I’ve had the exact same thing happen on my system about 4 or 5 times since I’ve been using Avast 5 and 6, and I’ve had no reason to suspect that it’s anything other than a minor, harmless glitch. Whenever it says “ffffff-ff”, I simply do a manual virus definitions update and everything seems to be normal again. You can do a clean re-install if you want, but honestly, I don’t think it’s necessary.