I was just able to log on to 2021. It was a bit slow to do so. I created a pop up that said I may need an update, but that did eventually go away. Sometimes I have found that pop blocks getting to the program. Use Ctrl + Tab to find that pop up window, if it is there and close it. 

If that fails, use Ctrl+Alt+Del to start Task Manager and close 2021 if it shows as open. 

Maybe run Tool Hub to reinstall that year.  https://accountants.intuit.com/support/en-us/help-article/system-responses/fix-common-problems-error...