First off, I guess it's possible to have an extension of .db, but usually for an Access db, the extension is .accde or .accdb.
The record is gone when they come back from lunch, or back into the db? Are you sure they are running the same .db?
I suppose some VBA code or a script could change the .db name, the big question is really? Or why?
Who developed your .db?

Joseph Thomas

Access often will append the computer name to the end of the file name if you try to run it from a cloud sync server, such as OneDrive. It will often prompt the user to save the database to a local folder. This may very well be the reason that the changes aren't saved because if they never make the local copy to work from, access doesn't typically like to run from cloud sync locations, essentially becoming read only in some instances.

If you're running from such a network, you should watch Richard's File Sharing for a better understanding.

Thomas sorry, it is the generic file extension, perhaps .accdb.

Donald I am using OneDrive, I have an office in the Philippines and found OneDrive faster to access, and suggestions for improvement?

Joseph the File Sharing video I shared earlier shows how to create a "Check Out" system for your database if you must use One Drive, but that's not optimal. Other options include moving your back end files to SQL Server or using something like Access Database Cloud.