>Interestingly if I include CLEAR PROGRAM in my Main.prg on the way out while shutting the app down, it works ok, just as if I issued it from the Command Window. Ok, a workaround ... but I want to know what and why in case it comes back in a more malevolent form or time. :-)

Okay, even more drastic :) Have you tried commenting out all that code, every reference to the menu, and creating a fresh *extremely* simple TL menu that does nothing at all, make sure that runs fine.

Then, add your regular menu components, oApp code, SYSMENU code, etc, just one piece at a time, to diagnose exactly when the error first appears?

I know it's a PITA, but at this point, that might be the only sure way to pinpoint it.