I submitted below as a bug because it has now happened to both me and my colleague. I have copied below the same information from my bug report.
Basic info: FM 9.0p.255, OS 64 bit, Windows 7
We have just upgraded to the new version and this is a serious thing if you don't keep backups! You will never know when it is going to disappear.
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Bug report:
When working with a Framemaker document it is unexpectedly deleted with no reason from the computer/network - this includes the backup.
The user did not delete it and it was an active document. There are different instances where the document would disappear. Below is one example of the steps taken.
Steps to reproduce bug:
1. Opened FM file.
2. Saved as an MIF file.
3. Closed FM file
4. Opened MIF file.
5. Edited the color definitions.
5. Clicked save button to save the mif file back to the source fm file.
Results:
Error message says that the file with extension .fm does not exist or has an unexpected extension. The .lck file exists but the .fm and backup files are gone.
Luckily I had the mif file and could rename it to a .fm file in this instance to recover the document. My colleague lost all versions (.fm and backup).
Expected results: that you would be able to replace the old version that is still on the network or computer.