I am having this same problem. I just cleaned up my active directory computers who had not changed their passwords in 60 days. After the cleanup I restarted lansweeper and saw many of them disappear. I checked the non active computer list and see may of the ones I deleted there still. I can still do a search on them and bring them up in lansweeper.
I do get these errors on some machines "The specified domain does not exist or cannot be contacted" but none of these machines are the ones in question. This seems to be a seperate issue as the domain these machines are on is the same as the one others were cleaned up off of.
