Do you see this error message when you start Firefox?

This error happens when a database file that stores bookmarks and browsing history (places.sqlite) and related site icons (favicons.sqlite) can’t be accessed by Firefox. This article covers possible solutions.

If you don't see the error above, try one of these articles instead:

• Recover lost or missing Bookmarks
• Can't add, change or save bookmarks - How to fix

Solution 1: Restart your computer

The most common causes of this error are another program using the file or a problem with the file that was caused when the computer was shut off unexpectedly (like a power failure). The good news is that most of the time, simply restarting your computer and then restarting Firefox is the fix for both problems.

Solution 2: Create a new database

If restarting your computer doesn’t take care of things, you can fix this by having Firefox create a new places and favicon database for you. Don’t worry, it’s not as hard as it sounds.

Part 1 – Open your profile folder

• Click the menu button , click Help and select More Troubleshooting Information.From the Help menu, select More Troubleshooting Information. The Troubleshooting Information tab will open.
• Under the Application Basics section next to Profile FolderProfile Directory, click Open FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.Your profile folder will open.

Part 2 – Create a new database

1. (Optional) Create a bookmark backup file.
2. Click the Firefox menu and select Exit.Click the Firefox menu at the top of the screen and select Quit Firefox.Click the Firefox menu and select Quit. Wait until Firefox has completely quit.
3. In the Firefox profile folder find and delete (or rename) the favicons.sqlite and places.sqlite files.
   • You can rename instead of deleting a file to keep it as a backup. Right-click it and select Rename from the context menuClick it once to select and click a second time the file name to make it editable, then add .old to the end of its name.
4. Also delete the favicons.sqlite-shm, favicons.sqlite-wal, places.sqlite-shm and places.sqlite-wal files, if they exist.
5. Finally, reopen Firefox.
   • When Firefox reopens, it will create new favicons.sqlite and places.sqlite database files. Your browsing history will be lost, but Firefox will automatically restore your bookmarks from the most recent bookmarkbackups file.
   • If your bookmarks weren’t restored, try the steps in the Recover lost or missing Bookmarks article.

Help! This didn’t fix the problem

If the above solutions didn't work, you may be able to resolve the problem with a new Firefox profile. You can use these instructions to create a new Firefox profile and set it as the default profile. When you restart Firefox, it will open with the new profile and, hopefully, you will no longer see the error message. You can then copy important data to the new profile and, if necessary, restore bookmarks from a backup file, if you have one.