Yikes! Here’s a tough one. Open a GEDCOM. Add another GEDCOMs. Delete the 1st. Now add another. This time, the Gedcom IDs for on the Families Organize page that should be the IDs of the 2rd GEDCOM are instead the IDs of the 1st GEDCOM. Also, when the program is closed, a protection exception error occurs.
Spent a couple of hours tracing this one, but haven’t found the cause yet. I think the deletion of the GEDCOM has messed up a few pointers. The exception is most likely caused when trying to close some structures that are already closed, and that is probably also caused by the incorrect deletion.