I too am ahving difficulty with the upgrade to 9.5.1. We have a network of 5 computers. 4 have taken very nicely to the upgrade. The one that hasn't is an 8600/300 with a Sonnet Crescendo/PCI G4 Processor Card running OS 8.6. VA 9.5 worked fine under this arrangement. With 9.5.1 we receive the dreaded Type 3 error. I have tried all those things listed in the previous posts and nothing seems to work. If anyone has any suggestions, I'd appreciate them.