I just created a table and got the message "Unknown, should never appear", followed by "[Untitled]", as the name of the tab. The only thing I can think of is that I was creating the table, wanted to copy paste the ID, inserteddate etc. columns from another table (too lazy to do this myself) so tried to save it first with a name but no columns (got an error) and second with just an INT column called YearJoined. Perhaps it's related to not having a primary key? Anyway, easy enough to avoid in future - just wanted to point it out so it could be fixed.
Kind regards, Clarkey