.....from time to time I will get a fatal error message when executing certain commands. The most recent occured this morning while using the REVCLOUD command, and a window came up that read "FATAL ERROR: Unhandled Access Violation Reading 0x0000 Exception at 340040cbh". It then asked if I wanted to save any changes, and then kicked me out of AutoCAD. I use 2000i with Windows XP Pro OS - I will sometimes get this error when using the STRETCH command as well. This error also happened periodically with my previous computer, also 2000i, but with Windows 98 as my operating system. Is this a 2000i bug, or is there some other explanation? Thank you for any input....this situation can be very annoying. ms-s