data lost

I got this problem some times ago with another database: some PDF are in database only as low res preview, but they referres to a file that does not exist. I have a file that referres to /Users/fabriziovenerandi/Documents/0database/ssis.dtBase/Files/Print job-4.pdf, but the “Print job-4.pdf” does not exist. I never deleted it, but there it is not more on my devon database…
how can I track this problem?

Did you restore a backup via the command Tools > Restore Backup… in the past?

I do not think I ever do a backup with this database.
Is there a log to consult about this?

There’s no log but you might check the filesystem too. Do/did you synchronize/copy the database from one machine/volume to another?

Yes, some times ago my hard disk begin to slow down, so I backup all datas to an imac, change hard disk, and backup again. but I do not get errors during the copy…

You might try this: Open the database package in the Finder and copy (!) the complete Files folder to the desktop. Then open the database and index the copied folder.

Finally, select the item referring to the missing file and click on See Also - is there an identical file in the drawer?

Yes.