A couple months ago, I got my mom to switch from Chrome to Firefox. She ordered a new computer from a computer exchange company recently, so she asked me to sync her browser data from her old computer to her new computer. I signed her up for a Firefox account, and when turning Sync on, it asked me to set up a second device. Since the new computer hadn't arrived yet, I decided to use Firefox Sync with another computer in the house. I installed Firefox on the device (it had never been installed before on that device) and hooked up her Firefox account. As expected, everything synced perfectly. The page telling me to connect another device still appeared, but I assumed that was because she hadn't connected a phone yet. When the new computer arrived the next morning, the old computer had already been shut down and sent to the company, and the other computer in the house was still running but didn't have Firefox open to the best of my knowledge. I installed Firefox on it (again, didn't come pre-installed and had never been installed before) and hooked up her Firefox account. This time, everything synced perfectly... except for the bookmarks. Only about 2-3 dozen of them transferred, along with one folder with a dozen more. (There were quite a few, potentially around 1-2 thousand.) The only bookmarks on the toolbar were the Getting Started page and a blank-titled bookmark leading to a "compose email" page. The rest were nowhere to be found. When I opened up Firefox on the other computer in the house, Firefox Sync had conveniently overwritten all of the bookmarks with what was on the new computer! Everything else, including the history, passwords, and add-ons, were preserved perfectly. I tried everything on [[Recover lost or missing Bookmarks|Recover lost or missing Bookmarks]] and [[Restore bookmarks from backup or move them to another computer|Restore bookmarks from backup or move them to another computer]] to no avail, since the other computer in the house didn't auto-backup the bookmarks after Sync transferred them. I even gave it a couple of days like the article suggested, and still nothing. There's no chance that the computer exchange company had anything to do with it, since they have a no-touch policy of 30 days in case there's problems with the new computer. Is there any chance that the bookmarks still exist somewhere? It's not a huge problem, since my mom told me that she's fine with the bookmarks being gone, and she would have ordered the old computer back if they were that important to her. I'm just unsure what might happen to the data in the future, or even what might happen to my own Firefox data, and hope that an answer might be helpful to others with the same problem but greater stakes. The browser data provided along with this article is that of my mom's new computer, and should be true for the other browsers involved as well -- except for the old computer, which was Windows 7.