Unrecognized database format: back end on mapped drive RRS feed

  • Question

  • A client computer is using Access 2016 on Windows 10 with Creator's Update to connect to a back end on a mapped drive to Windows Server 2016.  The day starts without issue.  Periodically (after hours or days of no problem), the database crashes on the client with the error, "Unrecognized database format "Z:\backend.accdb". The backend was created on Access 2010.  Before Creators Update I had no problem.

    I noticed that the backend.accdb lock file sticks.  It locks at approximately the time of the disconnection, and remains locked even after all clients are disconnected from the back end.  Deleting the lock file puts the backend in an unstable state and a repair must be performed.

    Other clients do not have this problem (windows 10, windows 7, Office 365, Office 2010).  

    The solution I have found is a backend decompile followed by backend compact & repair.  This is not acceptable for users.  I need a resolution.

    I recently installed other software on the client that would not launch on the Windows 10 Creators Update.  The fix was to turn off IPv6 on both the client and the server and reboot.  Could this cause the problem?  That's the only change I can think of that was made on the system.  If this is the cause, what is the resolution?  If this is not the cause, what is the resolution?

    Thank you.

    Sunday, June 3, 2018 4:20 PM

All replies

  • Hello SammieKay,

    Read the following blog related to this error (unrecognized database format) :

    Good Luck!

    Monday, June 4, 2018 6:34 AM
  • Hi,

    It notice that the issue is related to Access database. To better fix the issue, I move the thread to Access forum for more help.

    Thanks for your understanding.

    Best Regards,
    Winnie Liang

    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Monday, June 4, 2018 8:56 AM
  • Hi SammieKay,

    To narrow down this issue, I would suggest you make tests below:

    1. Turn on IPv6 both the client and server to check whether this is related with this issue.

    2. Uninstall Windows 10 Creators Update to check whether this issue still exist.

    Best Regards,

    Tao Zhou

    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact

    Tuesday, June 5, 2018 6:02 AM