First, copy your bookmark backups to a safe location since they gradually age out. Do this on both computers just in case. This will open your active Firefox settings (profile) folder: Help > Troubleshooting Information > "Show Folder" Look for the bookmarkbackups folder. It should contain numerous dated files with a .json extension. Copy those to a safe location (e.g, copy the entire folder to the desktop). You can restore any of those backups, but please note that they will completely replace whatever bookmarks you currently have on your menu. To restore backups, see this article: https://support.mozilla.org/en-US/kb/back-up-bookmarks-or-move-them-to-another-computer#w_restoring-from-backups You might need to go back a few days until you find the ones you're missing. If you want to save your current bookmarks in an alternate format so you can restore them as a separate folder and salvage individual items, check out this feature: [[Export Firefox bookmarks to an HTML file to back up or transfer bookmarks]] and [[Import Bookmarks from an HTML file]]. Can you get everything back?