Type about:support in the address bar and press Enter.
Under the Profile Folder section, click on Open Folder.

'''1. Check the Bookmarks Menu''' Click on the Bookmarks menu in the toolbar to see if your bookmarks are listed there. Sometimes they may just be hidden or not displayed in the usual way. '''2. Restore from Backup''' Firefox automatically creates backups of your bookmarks. You can restore them from a backup if you have lost them: Click on the Library icon (the one that looks like books) or press Ctrl + Shift + B to open the Bookmarks Library. In the Library window, click on Import and Backup in the toolbar. Select Restore and then choose a date from the list of backups. This will restore your bookmarks to the state they were in on that date. '''3. Check for Sync Issues''' If you use Firefox Sync, your bookmarks might be available on another device. Make sure you are logged into the same Firefox account on all devices and check if the bookmarks are synced. '''4. Check the Profile Folder''' If the above methods do not work, you can check your Firefox profile folder for the bookmarks file: Type about:support in the address bar and press Enter. Under the Profile Folder section, click on Open Folder. Look for a file named places.sqlite. This file contains your bookmarks and history. If you have a backup of your profile, you can replace this file with the backup version. '''5. Use a Data Recovery Tool''' If your bookmarks were deleted recently and you cannot find them in backups, you might consider using a data recovery tool to recover deleted files from your hard drive. This is a more advanced option and may not always be successful. '''6. Reinstall Firefox (Last Resort)''' If none of the above methods work, you might consider reinstalling Firefox. Before doing this, make sure to back up your profile folder (as mentioned in step 4) to avoid losing any other data. Additional Tips Make sure to regularly back up your bookmarks in the future. You can do this by exporting them from the Bookmarks Library using the Export Bookmarks to HTML option.