I have a third-party custom mdb file. It has a limited functionality custom menu. On one machine, it opens and shows a form (with further options). On another machine, it opens but that startup form doesn't show. I've copied the system.mdw file from one machine to the other (same location), so it doesn't seem to be a security issue. Both machines have Office 2007 Standard installed, as well as Access 2003 via Office 2003 Professional.