If you used a pre-release of Firefox 3 and then downgraded back to Firefox 2, you may find that you get an older version of bookmarks or passwords when you upgrade to Firefox 3. Firefox 3 only imports your Firefox 2 data once; and from that point on, uses the data which is in Firefox 3 format. Because you have used a pre-release of Firefox 3, you already have data in Firefox 3 format; which is what your latest installation of Firefox will use.

To retrieve your settings from Firefox 2:

1. Open your profile folder:

   At the top of the Firefox window, click on the Firefox button, go over to the Help menuOn the menu bar, click on the Help menuAt the top of the Firefox window, click on the Help menu and select Troubleshooting Information. The Troubleshooting Information tab will open.

2. Under the Application Basics section, click on Open Containing FolderShow FolderShow in FinderOpen Directory. A window with your profile filesfolder will open.
Note: If you are unable to open or use Fire​fox, follow the instructions in Finding your profile without opening Firefox.
3. At the top of the Firefox window, click on the Firefox button and then select ExitAt the top of the Firefox window, click on the File menu and then select ExitOn the menu bar, click on the Firefox menu and select Quit FirefoxAt the top of the Firefox window, click on the File menu and select Quit
   • Bookmarks and history: Rename places.sqlite to places.sqlite.bak and rename the .json files in the bookmarkbackups folder to .json.bak.
   • Passwords: Rename signons3.txt to signons3.txt.bak

1. Start Firefox again.

Firefox should then migrate your Firefox 2 data to Firefox 3. If this procedure doesn't work and you end up losing more information, you can restore by closing Firefox again and renaming the files back.