Bookmarks and History are stored together in a pair of database files: * places.sqlite (for titles, addresses, dates, etc.) * favicons.sqlite (for site icons) You can copy/paste these two files from the old Firefox profile folder to the new Firefox profile folder. However, if they are under different Windows users, there might be a permission issue you also need to resolve. You won't know until you try it. First, set Windows to show hidden files and folders: https://support.microsoft.com/en-us/windows/view-hidden-files-and-folders-in-windows-97fbc472-c603-9d90-91d0-1166d1d9f4b5 Next, check the old path: C:\Users\<old-username>\AppData\'''Roaming'''\Mozilla\Firefox\Profiles Usually the folder ending with .default-release is the one with the latest data, but please check everything you find here. The bookmarksbackup subfolder has dated files, so that can be a useful reference in addition to file modification dates. Can you find your old user's old Firefox profile here? If so, the next step would be to test whether this files work under your new user, details to follow if relevant. By the way, if there are no useful files under the above path, how about: C:\Windows.old\Users\<old-username>\AppData\'''Roaming'''\Mozilla\Firefox\Profiles