Hi all, we have a system that we can make crash at will simply by switching layouts. We are using AutoCAD 2004 16.0.0.124 (Sp 1a), on a dual Xeon 64bit 3.2GHz with 1GB memory (Video driver: NVIDIA GeForce FX 5200), running XP Pro. The system uses raided SATA raptor drives. That should make file access really quick we reckon. The problem can be resolved by diabling on-access virus scanning (McAfee VirusScan Enterprise 8.0.0). It appears that the anti-virus is interfering with AutoCad accessing the cached viewports or layouts. It is to say that none of the other machines has his problem, but then they have a different spec. None of them is a dual or has SATA raptors. That leads to the conclusion that the system is simply too fast. All information we get from AutoCAD is 'Unhandled exception'. Has anybody had a similar problem, or knows a way to make it work? Thank you for any suggestions. Ben