I updated to 3.6, lost bookmarks, have only a default profile so I restored. The bookmarks are now there but I can't get the dropdown list for many folders so I can't access these. Clicking on the arrow to the right of the folder name does nothing.
When I Click on some of the bookmark folders I do get a dropdown list of sites but not always all of the sites that were bookmarked. If I copy a nonresponding folder, the new copy can be accessed but apparently does not contain all of the sites. If I rightclick on a nonresponding folder and use 'open all tabs' Firefox will tell me the number of sites in the folder and ask if I really want to open so many.
ყველა პასუხი (1)
Sounds like a corrupted places.sqlite file.
See http://kb.mozillazine.org/Locked_or_damaged_places.sqlite