File corruption has started password required dialog box.
I recently had a file lock up and crash Filemaker Pro ver7.
I were trying to import excel data into the file to create a selected group. I had previously successfully done this with the same file and with another excel spreadsheet.
After restarting filemaker Pro and trying to access the file I get the required password dialog. I have never used a password on any of my files and can't access these files now.
The best solution would be to revert to a copy of your saved backup and import the files from the corrupt database.
Another solution would be to try to recover the database. (under File in Filemaker)
About recovering FileMaker Pro files