The first time this happened, I was working very late at night, and I wondered if I had been dreaming. Today, it happened again.
I have Filemaker 16 running on Windows 10. I noticed that every field in one table (the other tables were OK) had disappeared. I was tired, so I assumed I had made a mistake. I found an old version and replaced all of the fields. I then backed up my database. I opened it a few minutes later and the fields were missing again. I did the same thing again and this time, I backed up manually. The same thing happened. I rebooted Windows, and my table was fine. I backed up everything and everything was fine.
Today it happened again. This time, the first thing I did was reboot Windows, and the problem stopped again. Needless to say, I am very rattled. I depend on my three databases. I backed up all the data to Excel because I can redo my tables, but it the data is gone, I've lost 18 years of work.
Each time, the problem is when I close and back up the file. Each time it is solved by rebooting Windows