I ran into the same issue when I tried to install an older version of shotcut to a different folder. Ended up corrupting both versions. So what I did was I uninstalled thru the control panel.
Then I went ahead and deleted the entire old shotcut folder and the new shotcut folder including C:\Users\Username\AppData\Local\Meltytech\Shotcut. Then reinstalled the newest version from scratch. Might help to clear the registry settings when installing the new version.