In your second post you mentioned you also do not have your bookmarks any more. Do you recall anything unusual happening before this calamity, for example, did Firefox update? Did MacOS update? Did Firefox crash in an unusually severe way? Did you allow a small child or cat to operate your keyboard? Could you check for the following: (1) On your desktop: a folder named Old Firefox Data If you intentionally or accidentally triggered the Refresh feature, Firefox would have copied your old data into this folder. See anything like that? (2) Extra profiles in your Library To check this, start by opening your current profile folder. Either: * "3-bar" menu button > "?" button > Troubleshooting Information * (menu bar) Help > Troubleshooting Information * type or paste about:support in the address bar and press Enter/Return In the first table on the page, click the "Show in Finder" button. This should launch a new window listing various files and folders. Make a note of the name of your current profile in the address bar, then click up a level into the Profiles folder. Are there any ''other'' folders here? Let us know what you find.