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Do you see this error message when you start Firefox?

The bookmarks and history system will not be functional because one of Firefox's files is in use by another application. Some security software can cause this problem.

That happens when the file (named places.sqlite) that stores your bookmarks and browsing history can’t be accessed by Firefox. This article covers two possible solutions.

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

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 places database

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

Part 1 – Open your profile folder

  1. Click the menu button New Fx Menu , click help Help-29 Click the menu button Fx57menu , click Help and select Troubleshooting Information. The Troubleshooting Information tab will open.

    • Under the Application Basics section, click on Show FolderOpen FolderShow in FinderOpen Directory. A window will open that contains your profile folder.Your profile folder will open.
    Note: If you are unable to open or use Firefox, follow the instructions in Finding your profile without opening Firefox.

Leave the Profile folder open – go on to Part 2.

Part 2 – Create the database

  1. Click the menu button New Fx Menu and then click ExitQuit Close 29 .

    Click the Firefox menu Fx57Menu , then click Exit. Click the Firefox menu at the top of the screen, then click Quit Firefox.Click the Firefox menu Fx57Menu , then click Quit.

    Wait until Firefox has completely quit.
  2. In the Firefox profile folder, find and rename the places.sqlite file. Also rename the files places.sqlite-shm and places.sqlite-wal (if they exist).
    • To rename a file, right-click on it and select Rename from the menuclick on it once to select it and then click a second time on the file name to make it editable. Then add .old to the end of its name.
  3. Finally, reopen Firefox.
    • When Firefox reopens, it will create a new places database. Your browsing history will be lost but Firefox will automatically import your bookmarks from the most recent backup file.
    • If your bookmarks weren’t restored after creating a new places database, try the steps in the Recover lost or missing Bookmarks article.

Help! This didn’t fix the problem.

This problem has symptoms that are similar to a number of other problems. Maybe one of these articles better describes your problem.

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