We’ve seen similar error in our shop - only the users have the problem happen on every access attempt.
We resolved by shutting down the notes client and using Explorer or DOS to rename bookmark.nsf to bookmark.sav - then restart the notes client and new bookmark.nsf is created at notes client startup - old shortcuts from notes workspace are migrated into new bookmark file -
I am seeing this with e-mail clients, even when you open the file on the server end - so I would say it’s definitely not local settings… There is a large post on this topic already, but that seems to be addressing (non-mail) databases…