Sophos Anti-Virus: Installation Error 25010 - An error occurred while running the custom action 'UpdateSubscriptionInfo'

Error 25010. An error occurred while running the custom action 'UpdateSubscriptionInfo'. Contact your support personnel is displayed upon completion of the installation of a standalone Sophos Antivirus.

To resolve:

Ensure the process "AlUpdate.exe" is not running
Uninstall Sophos Anti-Virus
Uninstall Sophos AutoUpdate
Restart the computer
Delete "C:\Program Files\Sophos\" and/or "C:\Program Files (x86)\Sophos\"
Delete "C:\ProgramData\Sophos"
Delete HKLM\SOFTWARE\Wow6432Node\Sophos or HKLM\Software\Sophos
Delete HKCU\Software\Sophos
Download the latest 10.3 installer from Sophos
Install

Alternatively, within an elevated PowerShell prompt:

Remove-Item "C:\Program Files\Sophos" -ErrorAction SilentlyContinue

Remove-Item "C:\Program Files (x86)\Sophos" -ErrorAction SilentlyContinue

Remove-Item "C:\ProgramData\Sophos" -ErrorAction SilentlyContinue

Remove-Item "HKLM:\SOFTWARE\Wow6432Node\Sophos" -ErrorAction SilentlyContinue

Remove-Item "HKLM:\Software\Sophos" -ErrorAction SilentlyContinue

Restart-Computer