Not to be confused with the Access – Bug – Database is in an Unrecognized Format, KB4480960 released January 8th, 2018 breaks Access ’97 resulting in an “Unrecognized Database Format” error.

There are reports popping up in various forums

Incompatible Microsoft Access 97 and Windows 10 January 2019 Update

As of yesterday, Microsoft finally added an entry about this in the Known Issues in this Update section of the January 8, 2019—KB4480960 (Security-only update) webpage.

Their workarounds require changing file formats, changing versions of Access or changing database structure design! The easiest solution is to simply uninstall the flawed update, no?!

So, if you still run, or support, Access ’97 databases that sudden report an “Unrecognized Database Format”, just know it is nothing you have done, it’s just Microsoft again! As for how you resolve the issue, it is up to you, but for me redesigning a database, forcing clients to change software … just doesn’t make sense to me. Uninstalling an obviously flawed update is my privileged solution.