Access Lock Bug: Where the December 2021 Fixes Fail

[German]The security updates that Microsoft rolled out for Microsoft Office in December 2021 cause problems with Microsoft Access. Only one user can still access the databases. Microsoft did release fixes for the affected Office versions at the end of December 2021. However, there are users for whom these fix updates do not help. I briefly document here what is known about this and then try to report it to Microsoft.


Issues with security fix CVE-2021-42293

In December 2021, Microsoft closed the (Elevation of Privilege) vulnerability CVE-2021-42293 in Microsoft Jet Red Database Engine and Access Connectivity Engine with the following updates.

  • As of December 14, 2021, updates KB5002104 (Office 2013) and KB5002099 (Office 2016) have been released for the MSI versions of Microsoft Office 2013 and 2016.
  • For the Click-2-Run versions of Microsoft 365, Microsoft Office 2019 and Microsoft Office LTSC 2021, on the other hand, a Click-to-Run update with corresponding fixes was rolled out in December 2021 – there are no individual updates there.

In the blog post Patchday: Microsoft Office December 2021 updates (14.12.2021) causes Access issues, I had indeed pointed out that the two updates listed above affect access to Access databases. Now one user can still work with the database. Several users had contacted me and reported this problem.

Shortly after the security updates, Microsoft then added notices of issues to the support articles for KB5002104 (Office 2013) and KB5002099 (Office 2016).

After this update is installed, databases that are stored on a network share can't be accessed by multiple users simultaneously. Microsoft is aware of this issue and will update this KB when a fix is available.

The support article Error in Access when opening a database on a network file share describes the details of the errors in the still supported Access versions. It states that when opening a database on a network file share or links to another database on a network file share, the following error may be reported:

Could not use 'path to database.accdb'; file already in use..

Access error could not use 'path to database.accdb'; file in use

Alternatively, users receive a dialog box with the message The file could not be locked. The support post lists all updates that create this bug. Uninstalling the updates or Click-2-Run updates fixed this bug, but the vulnerability is then exploitable again – although Microsoft estimates the exploitability to be low. I had reported on this in the post Microsoft confirms issues in all Access versions after December 2021 Update


The fixes do not always help

Still in December 2021, Microsoft rolled out fix updates (hot fixes) for the various Access versions. I had given an outline of these fixes in the blog post Status of the access bug after December 2021 update (2022/01/03). But these fixes are not helping all users. On January 3, 2022 Simon Büding reported in my German blog issues within the following comment (I've translated his text):

I still have the Access 2016 access problem (we mainly use AccessRuntime 2016) with *.mdb files and *.accdb.

We are using Office 2019 Standard version 1808, build 10382.20020.

PC1 starts the database, it also opens a *.ldb (Microsoft Record-Locking Information).
PC2 also starts this DB and the error says "file could not be locked".

After the office update I restarted both PCs, unfortunately that wasn't it either. And uninstalling updates again, don't even get me started on that. Who else has an idea? Or has MS not fixed the whole thing 100% yet?

There are other similar comments on the German blog. While some people are able to work with Access in multi-user mode again with the fixes, other users are failing with the issues listed above.

Microsoft confirms: Fix not always effective

Either I overlooked it or it was only added afterwards by Microsoft to the support article Error in Access when opening a database on a network file share. In fact, Microsoft now writes about the following limitation where the fix updates do not help.

Note: If you are using Distributed File System Namespaces (DFS Namespaces overview | Microsoft Docs) to redirect a folder that contains an Access database, you will still see the issue that you cannot open the database for shared use, even with the fixed update.

Microsoft's advice is to use the direct path to the database to enable sharing.

A reader observation

German blog reader RalfH reached out to the German blog on January 4, 2022 with this comment (thanks for that), specifically describing his observations on the problem (I've translated the German text): 

1. with real network drives, the KB4484211 fix to the KB5002099 update works for us.

2.  with directories mounted as drive (e.g. subst G: c:\temp\LW) it unfortunately does not work.

Ralf writes that you probably have to work in the home office as described under 2. and that you are quite limited or unable to work. A VPN tunnel is out of the question in his environment – due to the constellation. Blog reader Martin gives some more hints in this comment:

If we map a drive with the database *.accdb via Net Use, the problem does not occur with us. We only have a problem with simultaneous access from multiple users when we want to start the database as runtime version (*.accdr) from this network drive.

If we start the runtime version locally from the server (C:\), the problem does not occur, unfortunately this is not a solution for our environment :(

Does anyone know any help here or can this also be reported to MS.

I am trying to report this observation to Microsoft now with reference to my English blog post (but I have no direct communication channels – Microsoft is a black box there).

Similar articles:
Microsoft Office Patchday (December 7, 2021)
Patchday: Microsoft Office December 2021 updates (14.12.2021) causes Access issues
Microsoft confirms issues in all Access versions after December 2021 Update
Status of the access bug after December 2021 update (2022/01/03)
Access Lock Bug: Where the December 2021 Fixes Fail

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