>After a certain sequence of events (switching between two different data directories using our VFP7 app), the CLEAR WINDOWS command produces an immediate C0000005 Fatal error. If you execute QUIT instead of CLEAR WINDOWS you get the same C0000005 error. Does anyone have any ideas on where to start looking. It's a legacy app whose replacement is mostly written, but which is needed for another couple of years. I mention this because suggestions to rewrite without using the DEFINE WINDOW command would not be helpful to us.

Not sure, if this is applicable, but you may use RELEASE WINDOW windowname command instead. Also try to create a simple reproducable scenario and send this as a bug to MS.