This has been happening very often in the past few monthsw. So basically I open firefox and there's this preference page that says welcome to firefox and another tab asking for sync from new account. This usually happens once every week. I enter my credentials for syncing and it asks to verify my login using my mail. After verifying firefox syncs with my account but after this the toolbar customization and my home page resets to default ones although my home page has the frequently visited sites it fails to save the pinned sites. Similarly my toolbar has add-ons which were removed from it and I have to make the changes again and again almost every week. The theme and the extension don't reset this only affects the homepage and toolbar. I've tried re-installing firefox but it does not help. Also starting it in safe mode does not help.