I'm sorry to hear about this problem.

First, if you haven't already, please do a normal shutdown and/or restart of your system. Restarting Windows can help by freeing up locked files, completing any deferred updates, and resolving temporary file permission issues.

Next, if Firefox still has bookmark problems, could you let us know what you get when you run the "Verify Integrity" diagnosis and repair function. That's here:

Open Firefox's Troubleshooting Information page using any of these methods:

• "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

Near the bottom, there is a section titled Places Database -- that's the file which stores history and bookmarks. Click the button labeled Verify Integrity. There may be a 10-15 second delay before results appear.

If all is well, the report that appears below the button should start with:

> Task: checkIntegrity
+ The places.sqlite database is sane
+ The favicons.sqlite database is sane
> Task: invalidateCaches
+ The caches have been invalidated
> Task: checkCoherence
+ The database is coherent

Does yours say that, or something else? You can select and copy the report, and then paste it into a reply for review and comment.

I have a very similar problem. 95% of my bookmarks are missing. The only things that remains are a few folders with their contents under Other Books and folders in the Bookmarks toolbar. All the "unfoldered" bookmarks in Other Bookmarks and elsewhere are gone. I'm also on Firefox 134.0.2

I followed the steps described above by jscher2000, and when I click the Verify Integrity button for the Places Database, I get this report:

Task: checkIntegrity - Unable to fix corruption, places.sqlite will be replaced on next startup > Task: checkCoherence - The task queue was cleared by an error in another task. > Task: expire - The task queue was cleared by an error in another task. > Task: vacuum - The task queue was cleared by an error in another task. > Task: stats - The task queue was cleared by an error in another task. > Task: _refreshUI - The task queue was cleared by an error in another task.

What else could I try to save my large collection of bookmarks?

I followed the steps described above by jscher2000, and when I click the Verify Integrity button for the Places Database, I get this report: Task: checkIntegrity - Unable to fix corruption, places.sqlite will be replaced on next startup

When Firefox creates a fresh places.sqlite, it should auto-populate your bookmarks from the latest automatic backup. If your latest automatic backup was incomplete, manually try restoring an earlier one from the available files on the Restore menu. See: Restore bookmarks from backup or move them to another computer. The menu should indicate the creation date and item count, so you can tell at a glance whether there was a major shrinkage event at some point.

Thank you for the quick reply! Unfortunately the manual restore also doesn't work, with the error message: "Unable to process the backup file." I've tried multiple dates with the same result. I can see that the count of bookmarks remains very stable, with incremental increases that seem consistent with the rate that tend to bookmark things. Any other thoughts? (I appreciate your inclusion of links to step-by-step instructions, because I am not a maven in this area.)

It would be useful to check whether the files are readable. They are compressed, so they look like gibberish if you open them in an editor, but I have a converter that reads a bookmark backup file and lets you save it as an HTML-format "bookmarks.html" file. If you want to try that, you can find it at either:

• https://www.jeffersonscher.com/ffu/bookbackreader.html
• https://jscher2000.github.io/Firefox-File-Utilities/bookbackreader.html

To access the file, you can drag and drop from a separate Windows File Explorer window -- see the steps in the following article to open that window: Profiles - Where Firefox stores your bookmarks, passwords and other user data.

Alternately, you can use the Browse... button and type or paste the following shortcut path, then click into the "default-release" folder and check whether its bookmarkbackups folder has the latest (or maybe it's in a different profile):

%APPDATA%\Mozilla\Firefox\Profiles

I realize this is all rather arcane, but when things don't work normally...

Anyway, if the file is readable and the "bookmarks.html" file is readable (this you can test in a normal tab), you can try importing the file using the steps here:

Import Bookmarks from an HTML file

If *that* doesn't work, hmm, maybe we can collect some error messages through a different console.

I'm not technical so I apologize for my response. Maybe someone can make it more user friendly.

This is like the 4th time this has happened to me in the last year. Just long enough for me to forget what I did to get them back, but I think it has been different every time. Last time I think it just randomly processed after many attempts. I should probably try saving them myself. They aren't actually gone. I was able to remember some of the pages I bookmarked and when I went to those pages via the browser the little blue bookmark star was there and when I click on it the folder(now missing) I had it in was named. I just didn't have access to the list of folders. I also couldn't make new bookmarks.

Now this time I had already tried a PC restart and refreshing Firefox so I'm not sure that they are required steps. I opened Old Firefox Data folder. This was already on my desktop from previous issues I believe. The names of the folders inside are jumbled. I opened the one with the most recent date. Then opened the Bookmarkbackups folder. I selected the file with the most recent date (also the largest file because I'm terrible at deleting the old ones). I was asked what to open the file with, I double clicked on Firefox and a browser page opened and a window asked if I wanted to open with (application) or save the file. I chose to save the file. This process took a few minutes and locked windows up for a bit but when it was done my bookmarks were back. I am able to make new bookmarks as well but you'll have to search for where you want to save it instead of their being a drop down of the most recent folders.

I hope this works for you.

Just want to add that every time this has happened to me I was using Youtube. Now I've used Youtube a lot without this happening but every time it did happen I was there.