"database disk image is malformed" generally means the file is corrupted. To rule out a locked file, you could do a regular Firefox exit, and a regular shut down and restart of your system. But assuming the problem continues, we generally suggest giving up on the file and starting fresh. Firefox will migrate your last bookmark backup but you won't have any history. I'll give the steps for that in a moment. Meanwhile, if you are a tinkerer, you could look at the following article: https://developer.mozilla.org/docs/Mozilla/Tech/Places/places.sqlite_Database_Troubleshooting ---- Open your current Firefox settings (AKA Firefox profile) folder using either * "3-bar" menu button > "?" Help > Troubleshooting Information * (menu bar) Help > Troubleshooting Information * type or paste '''about:support''' in the address bar and press Enter/Return In the first table on the page, on the Profile Folder row, click the "Open Directory" button (the label on this button may vary). This should launch a new window listing various files and folders in your file browser. Leaving that window open, switch back to Firefox and Exit/Quit, either: * "3-bar" menu button > Exit/Quit * (menu bar) File > Exit/Quit Pause while Firefox finishes its cleanup, then rename '''places.sqlite''' to something like '''placesBAD.sqlite'''. If you see journaling files named places.sqlite-shm and/or places.sqlite-wal, I think it's best to remove those or similarly hide them by renaming. Start Firefox back up again. Does Firefox recover your bookmarks?