Overview
When the auto-updates are set to run (by default on Saturday at midnight) or when triggered manually, the update will fail and the following error message will be generated:
Failed to Apply Patch: System.Runtime.InteropServices.COMException (0x8000FFFF): Catastrophic failure (Exception from HRESULT: 0x8000FFFF
Process
In order to resolve this, please upgrade to at least 2015 SR3.