Can't modify layout of databases moved to a new Mac.
Recently upgraded to a new 27" iMac. (Some months earlier, I upgraded from FMP 7 to 12.) Now, when I want to modify the layout of at least one database (so far) I get this: This action cannot be performed because this file is not modifiable. I can still make entries to the existing fields and work with them, but can't change the layout at all.
I've searched for anything that would give me permission to do so, tried changing the Sharing & Permissions:, to no avail. What am I missing please?