Access 2010: Unrecognized Database Format

I’ve been seeing more and more people having problems with the Unrecognized Database Format when creating or modifying an Access 2007 (accdb) format database in Access 2010 and then trying to open it again in Access 2007.

The issue appears to be that Access 2010 does not have its own file format. When you add a feature that is specific to A2010 (like the navigation control, data macro, or calculated column), that file becomes forever unreadable to A2007, even if the new feature(s) are removed. The solution appears to be:

  1. Remove all the new features from the file in Access 2010
  2. Create a new, blank accdb format database in Access 2010
  3. Import all the objects from the old database to the new.

The file will then be readable by Access 2007. The following link explains it more in detail.

I’m told that it is also possible to make the original file A2007 readable by removing the A2010 features and then making a minor edit to the file in a Hex editor.  But I’d be wary of that approach. Importing the objects to a new database is safer, more reliable, and frankly simpler.