I have never faced such a problem before, so I am writing here. One of my .mdb files stopped opening due to an error and, apparently, the data in it is now incomplete. I have no idea what can be used to extract data from an unsuccessful document.

It is similar on one of my situations. I tried many various methods to solve it. But appeared my database was crashed. If so, I would suggest you to overcome it via various methods, one of it described in the following, another might to search in Google or Yahoo more solutions to help you.

Restore file access from corruption

This article may help if your database is already corrupt
Before doing anything else, make a copy of the corrupted mdb file while Access is NOT running, and without overwriting any earlier backups. This lets you try different approaches and sequences if necessary.
Next, try the access recovery. This very simple solution may work with corrupted indexes, and might even get rid of a corrupted object:

If this does not work, follow the steps for the symptoms of your corruption below.
https://access.recoverytoolbox.com/