Sounds like you know where to look, and I would have noting to say that you forgot.

I checked my own bookmarkbackups folder in my profile, and it appeared empty, then I checked for the restore files in the Library List same as from Bookmarks Menu > Show All Bookmarks > Import and Backup > Restore > ... and everything was there. So I brought Firefox down, backed up my entire current profile, then removed read-only flags and hidden files, looked inside bookmarkbackups folder and everything was there. I'd know if I was missing the previous days bookmarks. (I'm on Windows 7)

Maybe you should check on your Mac for hidden files and read only files. How do you know your bookmarks are 4 years old, from the bookmarks that show up in your bookmarks, or are you looking at html files. Bookmarks and history are in places.sqlite and the bookmark backups are .json files and are hidden files until you make them not hidden. I was always able to look at them before though without doing anything.

By the way I don't want problems with not having several current bookmark backups so I had upped my backup count from 10 to 12 when I started on Firefox 4.0. Before Firefox 4.0 the default was 5, the default is now 10. After reading your post, I just now upped mine to 15.

Please check your files again, ans so backup your entire profile. I don't work with a Mac so can't tell you if you have write-protected files or hidden files interfering with what you see. Someone may have to help you with that. If you have your backups showing in your library list you have what you need just verify the bookmarks in your library list.

add a Last Modified column to your bookmark list (right click on a column header to add), search on colon (":") then sort Last Modified on date. look at top and bottom of that column for those that have dates anyway. That style I installed did everything but the Library list.'

• See http://kb.mozillazine.org/Sorting_and_rearranging_bookmarks_-_Firefox

As far as the replacement of the dog-eared white sheet favicon for files not having one with dotted outline favicon that is certainly not a problem. The old certainly look better, so I've updated mine

In order to install and test styles easily install the "Stylish" extension (248.8 KB)

• https://addons.mozilla.org/firefox/addon/stylish/

Fx 8 - Restore default favicon on New/Blank Tabs

• http://userstyles.org/styles/56126

Did you check the file size of all the JSON backup to see if there is still one large enough to have all the bookmarks?
You can also check the Time Machine for older backups or a working copy of places.sqlite

A possible cause is a problem with the file places.sqlite that stores the bookmarks and the history.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.com/kb/Bookmarks+not+saved#w_places-database-file

Time Machine saved me. I reverted to a saved Nov 10 Firefox "Profile" file to reestablish all of my bookmarks. I tried this three times in Firefox 8 and every time the bookmarks would begin to vanish. I finally uninstalled FF8, reinstalled FF7, asked Time Machine to revert to the saved "Profile," and I am once again whole. I'll add my voice to the many users who are exasperated with the numerous Firefox revs that in my case led to 8+ hours of system struggles that I had no time for.