After upgrading Plesk, some pages fail to load with one of the following error messages:
404 Page Not Found
TypeError: Cannot read property querySelector of null
TypeError: Cannot read property 'map' of undefined.
The upgrade process was interrupted, and Plesk was upgraded partially.
Connect to the Plesk server via SSH (Linux) / RDP (Windows Server).
On Windows Server, start a command prompt as an Administrator.
Start Plesk Installer to complete the upgrade:
# plesk installer update