During the last week I have had the same issue come up on two computers. When starting firefox, the previously saved windows come up blank (no tabs, no content) and nothing works (no opening new tabs or urls). I was able to get firefox back to working condition by renaming extensions folder and then copying extensions one by one back to normal extension folder. When I copied 'newtab@mozilla.org.xpi' the issue came up again. Also, the new tab extension keeps auto adding it self every other boot. Firefox: 144.0 (64-bit) - Mozilla Firefox for Ubuntu - canonical - 1.0 OS: Kubuntu 24.04.3 LTS x86_64 I am using the (unsupported) compact mode for firefox UI density. the manifest.json for newtab: {"manifest_version": 2, "name": "New Tab", "description": "", "version": "145.0.20250919.173227", "browser_specific_settings": {"gecko": {"id": "newtab@mozilla.org", "strict_min_version": "142.0a1"}}, "hidden": true, "background": {"scripts": ["webext-glue/background.js"]}}