Repairing a Corrupt MS Access Database

Unrecognized Database Format Error

An interruption, such as network connection loss or improper shutdown, can result in corruption of your MS Access database.  Fortunately, you can repair the database yourself in a few simple steps.  If a database has become corrupt, you will see an error message that contains the following:  "System Error: Unrecognized database format..."

Unrecognized Database Format Dialog

The System Error will state the most accurate cause of the error message.  In this case, you will also see the file path to your corrupt database in the error message.

How to Repair a Corrupt MS Access Database

  1. In File Explorer, follow the file path from the System Error message to locate your database.
  2. Open your database.  You will see a message (like the image below) that says “Microsoft has detected that this database is in an inconsistent state and will attempt to recover the database…”
Inconsistent State for Database Dialog
  1. Click OK and MS Access will automatically begin repairing the database.  As stated in the dialog’s message, a backup copy will be created during this process.
  2. After the database is finished repairing, you should open some of the major tables in your database (such as tblEquipmentMaster, tblCalibrationHistory, tblModelNumbers, tblStatusCodes, etc.).  These tables all use an AutoNumber data type as their Primary Key(version 8.11.9 and older), which can cause duplicate values during an interruption or if multiple users attempted to execute a write operation simultaneously.

    Since the corruption of the database likely occurred during a database transaction, you should check the tables you use regularly to ensure all of the records are intact.

  3. Sort the columns in ascending/descending order and if there are any corrupt records, you should see multiple pound signs ######### or "#Error" in those rows.
  4. If MS Access is unable to successfully repair/recover some records, the names of those objects (records, tables, queries, etc.) will be placed in a Recovery Errors table.
  5. If there are any corrupt records, be sure to delete them from the database.
Recovered Database Dialog

Your database is now repaired.  It is highly likely that the corruption in your database is completely taken care of after this process, however if you would like to take an additional step just to make sure, you can use the Repair Tool in MS Access.  It is located in the Database Tools tab > Compact and Repair Database.  This will attempt to repair the database, if needed, and shrink the size of the database by getting rid of any unused space.

You should backup your database regularly to ensure you always have a copy of the data in case of any accidental deletion, network/computer malfunction, corrupted/missing records, etc.  Refer to our help topic on Backing Up and Restoring your Database to learn more.

Get Ape Support

If you do not have MS Access installed, lack sufficient permissions to perform the above steps, or you would like us to assist in this process, we can repair your corrupt database for you!  If you are one of our customers with a current SMA, we can perform this service for free.

  1. Zip up your database file by right clicking the database and select Send to > Compressed (zipped) folder.
  2. If the database file is too large to send as an email attachment (i.e. more than 5 MB), you can use a cloud service, such as Dropbox, to upload the file instead.
  3. Send us an email at and attach the zipped folder or a link to your uploaded database file .
  4. Please be sure to include a short explanation, screen shot of the error message you are receiving, or simply let us know that you need assistance in repairing a corrupt database.
  5. We will repair your database and send it right back to you.