Hi, sorry that is not possible. Data deleted is deleted on both ends and even if was not that is not how Sync works. You do not mention another device that you are Sync'd with where you could recover your data that way.

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 these article.

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

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.

• https://support.mozilla.org/en-US/kb/how-do-i-set-sync-my-computer#w_connect-additional-devices-to-sync_

Please let us know if this solved your issue or if need further assistance.

Wow that's unfortunate, I'll be more careful from now on

If you use Sync then best is to disconnect Sync temporarily during troubleshooting.

Try to restore the bookmarks from a JSON backup in the bookmarkbackups folder.

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

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