I installed Firefox onto this new computer, and it was working fine. After a (possibly unrelated) Microsoft Windows update, Firefox stopped working correctly. Now all windows (except "Settings") are completely blank. I can't sign into my Firefox account, because the sign-in window is also blank. I don't know if this helps, but I've noticed that when I click on the "Firefox View" button in the upper-left corner of the screen, I see a box that says, "Switch seamlessly between devices" and includes a progress bar that indicates it's "11 % complete", which it has continued to say for three days. I've refreshed, uninstalled, and reinstalled Firefox several times and get exactly the same result (including the "11% complete" notice in Firefox View). Please help -- I've used Firefox for years and would very much like to continue to use it on my new computer, but right now, I'm stuck with Microsoft Edge (which is working fine ... but I love Firefox)!