Sorry you have such a problem. Obviously Firefox shoud not lose bookmarks on upgrading. I wonder what is going wrong for you that it happens on not one but two computers.

Find your profile by using the button in the troubleshooting page. Keying in about:support and pressing Enter is a quick way to do that. It probably makes sense to back up your Firefox profile at the same time. That helps preserve any information including bookmarks.

Next with Firefox closed. (Sorry this is going to mean you lose History) rename the profile database places.sqlite to places.sqlite.old With any luck you will have the bookmarks back when you restart Firefox.

See also

• Profiles - Where Firefox stores your bookmarks, passwords and other user data_how-do-i-find-my-profile
• Back up and restore information in Firefox profiles
• Can't add, change or save bookmarks - How to fix_create-a-new-bookmarks-file

It worked (mostly). Though now my bookmarks are messed up, and their icons gone, I guess I'm lucky to have them back in this condition!

Glad that at least partially worked. It should have restored the latest good copy of Bookmarks, and quite possibly that loses the favicons, but they should come back as you visit the sites involved.

If you did backup the profile you have the oportunity to try the alternative bookmark backups. If you try that it is probably best doing so in a new additional profile otherwise you will overwrite the recently restored bookmarks.

Do you use Firefox Sync by the way, that will sometimes badly mess up bookmarks collections.

There is an addon that should help with getting the icons back

• FavIcon Reloader 0.8.1-signed https://addons.mozilla.org/firefox/addon/faviconreloader/

Recently I was told this addon may work better

• Bookmarks Favicon Images 1.0.5 https://addons.mozilla.org/firefox/addon/bookmarks-favicon-images/

No, I don't use Firefox Sync.

Regarding the bookmarks, for some reason, they appear to have been reordered, but can't tell based on what criteria... It's neither dates or alphabetical. That's odd, but I'll just manually reorder them if I have to.

Regarding the icons, well, FavIcon Reloader 0.8.1 doesn't do a thing (no menu, no way to acces it, no window will open, etc...), and Bookmarks Favicon Images 1.0.5 allows me to manually select custom icons for my bookmarks. and not to automatically refresh them. Given I got 200+ bookmarks, well, you got the idea...