Hello Try this ease Fix https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks and also from https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

Did you try to restore an older compressed .jsonlz4 backup?

You can check for problems with the places.sqlite database file in the Firefox profile folder.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

• Places Maintenance: https://addons.mozilla.org/firefox/addon/places-maintenance/

Note that if you haven't closed Firefox yet then see if you can use "Organize > Undo" in the bookmarks manager (Bookmarks > Show All Bookmarks) to undo this action and restore lost bookmark(s). The Organize button is the first of the three buttons next to the Back and Forward buttons on the toolbar in the Library (Bookmarks Manager).

I see that you marked all answers as unhelpful, so I assume that you still do not have these bookmarks.

Did you try a search in the Bookmarks Manager (Library) or sidebar in case you have moved these bookmarks by accident to another folder?

Did you try to restore an older JSON copy from the bookmarkbackups folder that Firefox creates automatically?

• Bookmarks > Show All Bookmarks > Import & Backup > Restore

The name of a backup includes the number of bookmark items.

• bookmarks-YYYY-MM-DD_<item count>_<hash>.json

• https://support.mozilla.org/kb/restore-bookmarks-from-backup-or-move-them