Yes, that's the one. You basically will do the usual Avast Uninstaller Tool in Safe Mode as usual, then run this other tool to get rid of remnants. I'm wondering if these remnants are causing your problem since you are going from a higher version to a lower version. I realize it will take a while, but as you said, you've been doing this so many times, it should come a little bit easier. You may want to sign off-line to speed things up, then report back after doing it on one machine to let us know if it worked. Does that sound acceptable to you?