I been using Filemaker since version 7, and never had this issue. But with FMP12, I've had layouts that spontaneously disappeared from a file. This happened twice in the past few weeks. I don't know the exact sequence of steps, but I think it might be related to duplicating/renaming layouts.

Anyone else run into this problem?

The only time I've ever encountered things like this has been when there have been multiple copies of the same file floating around -- which is a version control issue.

Is the file being shared? Where is it stored: on a network volume, local hard disk? Is there more than one copy?

Technically there SHOULD be more than one copy -- your backup! However to avoid such version control issues, make sure that all backups are inaccessible: the easiest way to do this is to zip them so that cannot be opened.

It could possibly be file corruption to, so check that out. And get your backups sorted. :D

The file is on a network volume, and I have been duplicating the file and renaming every hour or so, just in case it gets completely corrupted by fmp12. I don't follow your comments about backups, I only open one file at a time and Filemaker should not know or care about any other files regardless of their content or location.

Storage on a network volume is the WORST way to share a file. I'd suspect file corruption. Run the recover command over the file and see what the log reports.

The problem with multiple copies of the file is that it's easy to get them mixed up. If the solution uses related files then it's quite possible that FMP might open a copy of the file that is NOT the one you expect.