Hi

Thank you for your question about the Firefox Sync service.

It appears from your question, that you are using Firefox Sync as a back up service. This is not what Sync is designed to do. The Firefox Sync service takes a copy of the data you wish to include and transfers it to a second device (typically a mobile device such as a tablet or a telephone) running a copy of Firefox. The storage in between all attached devices is both temporary and fragile and is not stable enough to be (and is not designed as) a reliable backup service.

If you have a copy of your Firefox profile for desktop Firefox, you may be able to recover your bookmarks and other data. Please have a read of this article.

If you have a copy of your data on a mobile version of Firefox, please follow these instructions to connect it to Firefox Sync to copy your data.

I read your question a bit differently than Seburo did.

".... Firefox auto backup my bookmarks but I can’t find them in the tab where they should be. ..."

See this support article:
https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

"Firefox automatically creates backups of your bookmarks and saves the last 15 backups for safekeeping."
Those backups are saved in your Firefox Profile folder.

Problem is that a "factory reset" would overwrite / erase the Firefox Profile folder, so there would be nothing to restore.

Ah ok thanks. It’s called Firefox profile so I thought it was linked to my account. Thanks again