Never happened to me until yesterday and today, couple of times.
Proccess tab and users tab just are just blank - like there are not any programs running, whereas CPU, Memory, Disk just above the tabs showcase usage as normal.
Was about to restart the machine to fix it. The task manager was still opened underneath windows explorer and internet browser. Decided to closo both and miraculously the task manager refreshed from blank state to "typically working " mode.
I will hold on with the new user account thing as they suggest, but would be more than happy to track down the culprit for this untypical behaviour.