This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(128, 8%, 22%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EA%3C/text%3E%3C/svg%3E)
I had a client today who could not open their shared backend database. The system displayed the error “Could not lock file”.
I determined that Access was trying to open the file in exclusive mode, even though none of the normal methods to open the file exclusively were being applied:
• The File / Options / Client Settings / Advanced / Default open mode was set to Shared
• No command line /excl was being used
• The user had Full Control permissions for the shared folder containing the database
• Creating a new test database opened it exclusively, so that no other user could open it.
• The newly created test database could not be reopened if another user opened it,
• Several other users could simultaneously open the new test database without a problem.
The user had been using the database for normal operations for several days prior to the problem.
The user’s system has updated to build 16.0.14701.20248 today.
All other test users had build 16.0.14701.20226.
I rolled the user's Office installation back to 16.0.14701.20226 by using the Office Deployment Tool https://support.microsoft.com/en-us/topic/how-to-revert-to-an-earlier-version-of-office-2bd5c457-a917-d57e-35a1-f709e3dda841
The problem was solved.
Can anyone else confirm that this problem exists with the latest build of Access?
Neil Sargent
Smart IT Ltd
A family of Microsoft relational database management systems designed for ease of use.
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
The issue is with KB500299, you can read about it here:
https://blog.fmsinc.com/microsoft-access-database-cannot-open-error-could-not-lock-file-error-3050/
The problem is that it isn't just KB500299. It depends on your version of Access. There are different KBs and build numbers that all cause this issues. So it's a PC by PC situation.
Furthermore, there are now multiple reports that the latest 'fix' doesn't work in all cases. Beyond which there isn't, yet, a fix for all versions either.
I've been trying to keep me article up-to-date:
Same problem here.
All clients updated to 16.0.14701.20262. Problem still persists.
Lock files are left with 0 bytes.
I've read somewhere else, that using UNC instead of mapped drives could solve the issue.
I can't confirm this for my Environment: If I want to access via UNC onto an already opened database with Access Version 13801.21092 (2102 SemiAnnual), I get the same error :-(
According to Sven Tegelmos investigations I've tried some different fileshares (all with UNC-Access):
It seems to me, that the way of sharing the database causes the issue.
Without the IT knowledge about todays fileserversystems (I left the IT side of things 25+ years ago) do I think its the same I experience with greater descriptions so please check Philipps post Microsoft :)
I have now also tried to link applikation file to database file (BE) using UNC and that makes no difference. Same problem.