Fiat, I purchased and was running QB Pro 2021 Desktop until last Fall when Microsoft's update deleted IE11 and it's .exe from computers completely.  Try to reinstall all you want and pay an IT guy all you want, it's not going to work and QB Desktop is COMPLETELY USELESS now.

I STRONGLY suggest people switch to QB Online ASAP if they can even still get into their QB Desktop until Intuit actually fixes their desktop program to utilize ANY browser.  Otherwise, find another bookkeeping program and move on.  I've been saying this for over half a year now and apparently Intuit isn't interested in actually repairing anything.  June is two weeks away and Microsoft gave Intuit YEARS to get this fixed.