I have my system up to date and no updates are available. The O.S. runs fine with the exception until I launch firefox which causes what I would describe as a SEVERE screen tearing. The description would be LARGE horizontal bands of angled multi colored squares on both of my monitors. I am unable read or distinguish anything! However when I type on the keyboard I can see the large squares changing colors. This may be a graphic display issue. A push of the power button restart is now required. I uninstalled and reinstalled Firefox which changed nothing I can use Epiphany Browser, and run other applications just fine even FooBilliard++ with no issues until I launch firefox. Thanks Kadetsr