I didn't know about ISX, but from what I can read from the help file, unless you have at least one OLE Public class in your project, VFP will not regenerate a new GUID:

"Only those classes marked OLE Public in the Class Info dialog box of the Class menu will be created and registered"

>I disagree. That GUID is also used when an update to the EXE is sent out. If that GUID is not different, ISX will not overwrite the old EXE with the new one.