How Do I Fix MS Access Unrecognized Database Format Error

Summary: Are you having trouble accessing your database files due to the ‘MS Access unrecognized database format’ error? Does the error prevent you from opening a table or a form linked to a table? This blog discusses the workarounds you can implement to resolve the ‘Unrecognized database format’ error. It also suggests using an Access database repair tool to extract data from inaccessible database files when nothing else works.

How Do I Fix MS Access Unrecognized Database Format Error

You may encounter an unrecognized database format error when trying to open or work with an Access database file (.mdb or .accdb) stored on a shared network drive.

access unrecognized database format error

The error usually occurs when upgrading to Windows 10, particularly version 1803. However, there have been instances where users encountered the error when using Microsoft 365 Access Build 16.0.3.

Note: If you get a ‘3343 Unrecognized Database Format’ on opening a database using Database Access Object (DAO), refer to this Microsoft page for details about the error.

What Causes the MS Access Unrecognized Database Format Error?

Following are some of the possible reasons behind the error:

  • Bug in the Windows 10 version.
  • Corruption in the database because of an unsplit database, shared front-end, unstable networks, etc.

Workarounds to Fix MS Access Unrecognized Database Format Error

Note: Before implementing this workaround, check if you can revert to a previous version of Windows. For instance, you may rollback to Windows 1709. But, remember you only have 10 days to rollback your Windows version. If this doesn’t work for you, proceed with the following workarounds.

Workaround 1 – Use the ‘DisableLeasing’ Registry Hack

To fix the Windows 10 bug resulting in the ‘Access unrecognized database format’ error, Microsoft recommends disabling the leasing on the server with shared (back-end) database files. This is, in fact, the common solution that seems to resolve the problem. However, it has certain downsides. You need administrator privileges to apply the registry hack. Also, you may experience some performance issues.

The steps to apply the registry hack are as follows:

  • Open the command prompt as an administrator. To do so, type command prompt in the Windows search bar, then click on ‘Run as administrator’.
  • In the command prompt window, execute the following:
REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters /v DisableLeasing /t REG_DWORD /d 1 /f



  • Exit from the command prompt.

Now check if you can open the Access database without any issues.

Workaround 2 – Run Compact and Repair

If you’re using MS Access 365, the following steps may help you fix the ‘unrecognized database format Access’ error:

Note: Delete .laccdb file if you’re getting the error on opening an ACCDB database file. If the problem happens when opening an MDB file, delete its .ldb file.

Workaround 3 – Move the Database to a New Folder

Some users could fix the error by creating a new folder and moving their problematic database to that folder. Make sure to create the new folder on the same drive where the original database is stored.

What Else Can You Do?

Do you fear implementing the ‘DisableLeasing’ fix? Or, if none of the above solutions work for you, try to extract data from inaccessible Access database files (.accdb/.mdb) using Stellar Repair for Access software.

free download

Check out this video to see how the software helps restore a database encountering the ‘MS Access Unrecognized Database Format’ Error.


“Microsoft Access Unrecognized Database Format Error” may appear while upgrading the system or when a user tries to access Microsoft Access database file through a different application like Visual Studio. The error happens because of a Windows 10 bug. It may also be caused due to corruption in an Access database, which might occur when using an unsplit db, sharing the same front-end copy with multiple users, etc.

Unfortunately, Microsoft is still investigating the issue, and there is no permanent solution for the problem. However, applying the ‘DisableLeasing’ registry hack is your best bet to fix it. If you want to avoid the registry hack, try using the other workarounds. You may also consider using Stellar Repair for Access to recover data from the inaccessible database.

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