Firefox has lost a series of bookmarks. Not sure if it is a problem with Sync.
I routinely use Firefox on my Mac computer. A bunch of bookmarks that I used often have gone missing. These were put in a few months ago. The older bookmarks and the newer bookmarks are all there. I do not know if this is an issue with Sync. I would really like those bookmarks back.
You can check for problems with the places.sqlite database file in the Firefox profile folder.
- Places Maintenance: https://addons.mozilla.org/firefox/addon/places-maintenance/
If you use Sync then best is to disconnect Sync (temporarily) while performing maintenance/repair efforts to the places.sqlite database.
You can check the backups in the bookmarkbackups folder.
- Bookmarks > Show All Bookmarks > Import & Backup
Note that the file name includes a total item count.
- bookmarks-YYYY-MM-DD_<item count>_<hash>.json