Hi, it sounds like you are familiar with the Restore menu. When you look at the list on the Restore menu, it should show the item count for that backup (items = bookmarks + folders + separators). Do the backups seem to change drastically at some point in the number of items?

Ref. Restore bookmarks from backup or move them to another computer

If all the backups shown on the Restore menu are too small, it's possible your Firefox started up in a different profile. Please check the first section of the following article on how to check for other profiles: Recover lost or missing Bookmarks.

Any progress so far?

No, they're all the same number, and there are no other profiles aside from the default with the four basic bookmarks.

Are you using Sync?

You can check if you have the "Old Firefox Data" folder on the desktop in case the Refresh feature in Firefox has been used and a new profile has been created.

• https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-most-problems

I am using sync, and I do not have old firefox data, because I reinstalled windows.

Could you check for orphaned profile folders using this shortcut path in the Windows search box or the address bar of Windows File Explorer:

%APPDATA%\Mozilla\Firefox\Profiles

That shortcut address expands to this hidden folder:

C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles

Do you see any folders there that are not listed on the about:profiles page? If so, do their bookmarkbackups folder have any bigger files (the number of items is coded into the file name right after the creation date)?

There was no orphaned profiles, I did check before.

However, all my bookmarks came back just a few minutes ago with no interference on my part. It added to the ones I already had, so I have repeats now for the few that I had had remaining. I am not sure why this happened or what caused them to disappear or return, because I had forced it to sync multiple times over the last few days.