Resolving "Context toolbar not found. Bookmark design needs update"

A colleague of mine asked me about an error message a user of his got while in Lotus Notes. The error message stated that
 
Context toolbar not found. Bookmark design needs update.
 
The solution is pretty straight forward, and even indicated by the error message. By deleting the file called Bookmark.nsf and restarting Notes, Notes creates a new Bookmark.nsf file which solved the problem.