The server that I had to do a full restore on yesterday was scary…After it was plugged back in the domain it would not allow clients to authenticate. I suspected that this was due to the fact that it was restored from a tape over 2 weeks old and therefore the SAM on this server was out of date with the SAM on the PDC. Trying to use netdom (the one from supplement 4 to the resource kit) kept on coming up with access denied errors and was therefore not much use. Overnight I scheduled a reboot of the pdc and did nothing else to the BDC as I was going to attempt a fix this morning…however when I got there, the users were working away – I guess the reboot had synched everything up properly (thankfully)