I have been using nrfConnect for Desktop on Windows for many years. I have version 4.01 installed. I sometimes get prompted to upgrade but when I try to complete the upgrade it fails after downloading. I also get an error when I try to uninstall. The error says "nrfConnect for Desktop cannot be closed"
I have tried this immediately after rebooting and get the same problem. I have searched for any running application in task manager and it doesn't exist. I suspect some lock file is left behind from a previous crash, but I have no idea where to look.