I see in the screenshot that all tiles are pinned. Firefox stores the websites that are pinned in a pref on the about config page, so it looks that this eraser utility also messes with prefs.js in the profile folder. You can possibly keep a backup copy of this pref to be able to restore its value. *browser.newtabpage.pinned => websites pinned to a tile *browser.newtabpage.blocked => websites removed by clicking the X (Dismiss) button in a tile You will have to check the settings of the eraser to see if you can exclude specific data or contact its support (helpdesk).