What is supposed to happen is that when you install the beta, it detects that you already have a Firefox settings folder and it just replaces the program files. However, you're right that there is a small risk of data loss. A backup is a great idea. These articles should help: * [[Back up and restore information in Firefox profiles]] - all settings your active personal Firefox settings folder, also known as your Firefox profile folder * [[Restore bookmarks from backup or move them to another computer]] - just bookmarks