Hey Garrett. This is one of the most maddening problems I've seen with Sync over many years. I hate this dataloss bug with a passion. No one can determine why it happens but everyone agrees that it shouldn't happen. I really thought something this devastating would've been fixed by now but I believe since the Sync devs can't reproduce the conditions that cause the "reverse sync", they can't fix it the right way. Only guess how to fix it. Sadly, I believe your bookmarks are gone because Sync doesn't have extra backups of the data. I know this doesn't help you now but I feel like your feedback on my ideas would be critical to crafting a better solution to handle this disaster scenario. If you also have ideas on how this should be handled, please share! '''My ideas:''' * Create a permanent backup of bookmarks (a week's worth or more) on everyone's Sync account in case of accidental deletion - whether caused by Sync itself or the user's action. These bookmarks could also be deleted but only after going thru '''multiple''' prompts & a large warning explaining that deleting them will be permanent & they can never be restored. * Create a permanent backup for Passwords - even though this scares the security devs at Mozilla, I have seen too many cases where Sync passwords were completely wiped out by accident * Don't support creating a backup for Credit Credit formfill data. That is a ticking time bomb to be stolen by hackers. * Backup in a more resilient way more types of Sync data - not everything - but mostly Bookmarks, Passwords & Tabs * Allow Export option for bookmarks - that way if lost on a desktop, they can be reimported Overall, the Sync developers need to understand Firefox users treat Sync as a cloud backup. And it looks and feels like a cloud backup. So it needs to work like a cloud backup with reliable data retention. Bookmarks and tabs are the most lost Firefox data. Making them hard to delete & resilient to accidental deletion should be a priority. '''Side thoughts on too much data backups:''' Personally, I don't like the idea of everyone backing up their passwords to the cloud. I feel like this is dumbest thing anyone could do. Hackers love these cloud backups because of how many passwords they hold. When the LastPass and Dashlane password managers popularized this, I was against it. LastPass was finally hacked in 2022 in a massive way. Proving me right. https://krebsonsecurity.com/2023/09/experts-fear-crooks-are-cracking-keys-stolen-in-lastpass-breach/ Sep 5, 2023 "Security researchers say hackers have cracked open some of the password vaults stolen in the LastPass breach and used them to steal millions of dollars in cryptocurrency. The victims are mostly security-conscious people who stored their crypto seed phrases in LastPass." I won't be able to change user behavior on this but if maybe all browsers could start restricting saving webmail, bank and crypto passwords. This would be HUGE in preventing hackers from easily finding saved financial passwords inside a browser or cloud backup. But for bookmarks and tabs, I feel like they should have extra backups available to the user separated from the main area. That way if a reverse sync from a empty device happens, it can not idiotically erase all current backup data. Honestly there should be a way to detect this by now. But since I have lost hope that bug can be fixed, I propose more effort be invested in creating separate backups that can't easily be deleted without a user's confirmation. And allowing for exporting Bookmarks so they can easily be restored on a desktop.