I've been struggeling with this issue since the introduction of Unity Hub. EVERY time there is a upgrade and I'm asked to restart the Unity Hub, it installs the update and in the process removes the executable. So the last step "Launch Unity HUB" is checked, but I'm greeted with an error about the link pointing to a missing exe. And the previous desktop shortcut doesnt work due to the same issue. I've tried uninstalling and purging temp files, directories, registry etc to see if a complete reinstall solves the issue, but no. Every upgrade ends the same way i.e. missing exe and I need to download the Unity Hub manually.