I upgraded and noted as I was adding Creating a Table, the FMP17 adds various fields automatically—a "freebie". I assumed that the Primary Key was set up to add a number automatically... and imported data from an Excel file (saying yes to letting it do all automatic entries presumably Primary Key addition.
All good until I noticed a character that was apparently brought in that had question mark in a diamond (after the close parenthesis). So I erased it... (it appeared to be an unnecessary space on the Excel spreadsheet but may have been a non-Mac character) this is is on the entry for the airport code of ABR, Aberdeen SD (as in the screenshot).
But then Filemaker said something about the Primary Key, but it was not on this Layout. So I did a Cmd-L to add that field to the Table View. That's when I saw that column was empty—not what I had (foolishly) Assumed. And no matter what I do now, I get the dialog box about Primary Key Requiring A Value and that I MUST Enter A Value! Of course the Primary Key field is Unmodifiable. So this database is locked up and I do not know how to do anything to back out gracefully.
Rather than Force Quit FMP17 and go back to my backup, I thought "time to go to sleep" AND maybe one of you could suggest how to break through this without having to rebuild the two new tables.
And, Yes, I will not be so sloppy as to check the Primary Key and other nice fields I was given next time!
PS probably no one else had this problem yet but if it is a new kind of way to screw up, maybe you can consider helping us spare time database creators one more leg up and help us avoid this sort of problem.