found it:
In Windows Explorer, delete the ..\Mas90\Cm folder.
In Sage MAS 90 or 200, open Library Master / Repair / Data File Display and Maintenance (DFDM), and select Sy0ctl.soa.
Delete the [lC/M] ( l = ""ell""), and close DFDM.
Run File / Run / SVMUPD to update the menus and remove Custom Office from Library Master Main menu.
Note: SVMUPD rebuilds the LM Main menu based on the level records found in SY0CTL.