Sorry, that probably means that a file replacement wasn't successful and now there is a mix of older and newer Firefox files in the program folder.

Don't uninstall.

Is the problem on Windows? Try running the full installer from the following page to refresh the program files without touching your personal data:

https://www.mozilla.org/firefox/all/#product-desktop-release

The site should automatically detect your language/local preference (for example, U.S. English) but there is a selector to fix it if the sites guesses wrong.

Any luck?

I was desperate for a fix and I consulted YouTube and the video I found said to uninstall and reinstall. I did not want to nor did I believe it was necessary... but I did it anyway. And it appeared to be fixed... all my tabs opened... Except they didn't... open. All 52 tabs with their names, but all blank pages! So I closed that window and reopened another. And Firefox started up, but everything previous appears to be "lost." Stored passwords gone! History of previous session gone! I don't know about bookmarks; I was too scared to check.

Thankfully, history is intact, so I can refind all those previously open tabs, but all the passwords???? OMG!

So my question is now, is there any way to retrieve them? And how do I even check to see if bookmarks were saved? I don't mind reinstalling add-ons. I didn't use that many. But all the personal preferences and passwords.. GAAAHHH! What a pain they are gone!!!!

I followed the instructions in the video to a T. Everything should have been saved. I just wanted to get back to work and I didn't know how long it would be to get an answer here. Now I have WAY more work to do to recover everything (if they are even recoverable!) Of course, I should have just waited for your response in the first place!

Hopefully, you will have some equally helpful good news (with a simple fix) for me now.

Let's start with tabs. It sounds like you have Firefox set to restore previous session windows and tabs at startup. Blank tabs can indicate a problem in that file, but it's a little strange not to get the same problem each time if you restarted. Worst case, we could pull an older list. Let me suggest some things in a minute, but first two initial questions.

Did Firefox perform a Refresh? That would have moved your entire profile/settings folder to your Windows desktop inside an Old Firefox Data folder. If you have that check the freshness of its contents and if they were updated today or yesterday, ignore the rest of this reply.

Session history, saved logins, bookmarks, history, and add-ons are all stored in the same profile folder, so it is strange to lose some but not all. Or maybe you lost all but after signing into your Firefox Account, you got some back. Is that a possible scenario?

Next Steps:

(1) Please look for some files and back them up as follows:

You can open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > Help > More Troubleshooting Information
• (menu bar) Help > More Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, find the Profile Folder row and click the "Open Folder" button. This should launch Windows' File Explorer listing the contents of your current profile folder.

Saved Logins

Firefox stores usernames/passwords in a file named logins.json and the companion key4.db file stores a key needed to decrypt them. I suggest backing up these two files to a new folder outside your profile, for example, in your Documents folder or on your Desktop. Also, look for any other file starting with logins that Firefox might have set aside as possibly corrupt or unreadable. Not sure we'll be able to use them, but we should preserve them.

Session History

Back up the entire sessionstore-backups folder. You can right-click > Copy on that folder, then right-click > Paste in your backup folder you created for the previous step.

(2) Check for alternate profiles

If you haven't already, could you close out of Firefox and do a normal Windows shutdown and restart to complete any pending updates and release any file locks.

If Firefox again starts up without all of your data, could you check whether your stuff is available in a different profile, as follows:

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 profile that Firefox is currently using will have this:

This is the profile in use and it cannot be deleted.

Do you have any other profile(s) listed on this page? If so, you can check whether it is the one you were using recently by clicking its Launch profile in new browser button.

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.

Any progress so far?