Provided you saved your bookmarks in HTML format, there shouldn't be a problem. See [[Importing Bookmarks from an HTML File]] Try moving the file to your hard drive first if necessary. How did you update though? Via '''Help '''| '''Check For Updates''', or did you download the file from [http://www.mozilla.com/en-US/firefox/fx/?ref=logo Download Firefox 4.0]? If you did the latter, did you uninstall the previous version via Add/Remove Programs first? That also gives you the option to keep your bookmarks, customizations etc. You also need to delete the Mozilla Firefox folder at this location before updating: C:\Program Files\Mozilla Firefox