This problem has been posted a number of times and I've gotten no solution. About 3 weeks ago, I lost all my tabs when closing down my Mac. I have the function to have tabs when resigning on (it's worked fine for years), Also, all my desktop icons are increased in size to 1" by 3/4". Also, cannot download another browser. This is MOST irritating. Sometimes the answer I got from Mozilla was to connect with aa screen icon, but I didn't have the icon. I have download a new Firefox----no resolution. Last night I uploaded to Big Sur 11.75 I need good technical help. Dorothy