<i>Locking this thread.</i><br><i>Please continue here: [[/questions/1340999]]</i><br> I have used Firefox for many years, but last year it started to stop working for no obvious reason and after playing around with it for a while I started using another browser. However, I am Firefox user at heart and so recently installed the latest version (89). However, the same problem exists. I have: - started in safe mode - eliminated all extensions - I am using a completely new profile I can start up Firefox and it works for a few minutes , then with 4+ tabs open (not sure if that is relevant) it stops work - tabs don't load. I can write in the address bar, but nothing will then load up. When I close the browser down it appears to close down normally, but when I restart (immediately or minutes later) I get a box saying an "Firefox is already running but not responding. The old Firefox process must be closed to open a new window." Is it a sync problem? Look forward to getting any help/suggestions. Rob