Oh no, please don't delete things at this point. Could you check whether your stuff is available in a non-default profile, as follows:

Profile Manager Page

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list at least one profile and could list many. (Each profile has two folders and one or more buttons. Do not use any Remove buttons!)

The non-default profiles are the ones that have a button labeled Launch profile in new browser. Click that button to check what is in that profile.

If it isn't what you want, simply close that new window.

If it IS what you want, back on the about:profiles page, click the Set as default profile button for that profile so Firefox uses it automatically at the next startup.

Anything useful there?

Hi jscher2000,

Thanks for the reply. I did load the About Profiles earlier, and it didn't resolve the issue.

I've also searched for every possible element in the system that might lead to a clue. Not much.

However, I did stumble over an old bookmarks backup and loaded it. From maybe four years ago. While scrolling it, I saw "other bookmarks" and what appeared to be the most current version of the missing tabs. If not, it's close. Can't figure why that would be included with the old backup, but I'm not arguing.

I was able to restore those. That was the biggest issue. I've now created a new backup of the current setup, putting it in three locations including two external drives.

It's not perfect, but about 90% of normal. I can't yet recapture the add-ons (or even remember all of them), but that's for another day to worry over.

Thanks again.