>Where does the window come from that pops-up that says, "Invalid Input" when a .F. is returned from an object's Valid()? I have tried putting a wait window at different places (in the Valid and ErrorMessage methods) to no avail. It will show my message, but then it always shows the default one immediately after. FYI, this is partly a legacy and it may not actually be a Foxpro 5.0 default problem. Any ideas?

Try returning 0 instead of .F. This will not give a message but will prevent you from leaving the field, giving you more control of whatever it is you need to do.