INSTALLATION

The Firefox UserAgent or UA you used to post this support forum thread is Mozilla/5.0 (Windows '''NT 6.0'''; Win64; x64; rv:109.0) Gecko/20100101 Firefox/115 The NT 6.0 is Windows Vista so this likely means you are for some reason running Firefox 115 ESR in Windows Vista compatibility mode. Firefox 53.0 and later required Windows 7, 8, 8.1 as Fx 52.9.0esr was the last you could run on Windows XP and Vista. This is why you are very likely running in compatibility mode. If you are using Windows 7, 8, 8.1 then the ,most current Firefox you can run is the current Firefox 115 ESR version. If you are running Windows 10, 11 then you can use the current Firefox versions since 116.0 and later. https://www.pcgamingwiki.com/wiki/Windows_Compatibility_Mode After disabling running Firefox in compatibility mode and if it is on Windows 10, 11 then you should download current version at https://www.firefox.com/download/all/ as otherwise a internal Firefox update in Firefox 115 ESR will update to the older current version of Fx 140 ESR and not Fx 153.1.0esr..

Hello To complement https://support.mozilla.org/en-US/questions/1598818 As for me, i installed Linux, in dual-boot with Windows7