Server 2019 Cumulative Updates failing every month

Question

Hi all

A client is running Exchange 2019 on Server 2019 in a Hyper-V VM. Since the 2020-10 Cumulative Update (for Windows Server 2019), all CUs have failed to install via Windows Update. They have another Server 2019 VM which runs Active Directory and File Sharing and does not have this problem.

The latest CU "2021-03 Cumulative Update for Windows Server 2019 (1809) for x64-based Systems (KB5000822)" fails with error 0x800f0985 (some previous months CU have failed with error 0x80246007).

Things I've tried so far:
Download the CUs and install manually - CU installations fail with same error
Run sfc /scannow - no errors found
Reset Windows Update - CU installations fail with same error

Other relevant details:

Versions:
Server 2019 v1809 build 17763.1518
Exchange Version 15.2 (Build 595.3)

WindowsUpdate Log: 77912-ytw-exch-windowsupdate.log

Installed Hotfixes:

PS> (Get-HotFix | Sort-Object -Property InstalledOn)  
  
Source        Description      HotFixID      InstalledBy          InstalledOn  
------        -----------      --------      -----------          -----------  
EXCHANGE      Security Update  KB4512577                          07/09/2019 00:00:00  
EXCHANGE      Security Update  KB4539571     NT AUTHORITY\SYSTEM  30/03/2020 00:00:00  
EXCHANGE      Update           KB4486153     EXCHANGE\Administ... 30/03/2020 00:00:00  
EXCHANGE      Security Update  KB4549947     NT AUTHORITY\SYSTEM  17/04/2020 00:00:00  
EXCHANGE      Update           KB4494174     NT AUTHORITY\SYSTEM  20/05/2020 00:00:00  
EXCHANGE      Security Update  KB4562562     NT AUTHORITY\SYSTEM  15/06/2020 00:00:00  
EXCHANGE      Security Update  KB4558997     NT AUTHORITY\SYSTEM  04/08/2020 00:00:00  
EXCHANGE      Security Update  KB4566424     NT AUTHORITY\SYSTEM  21/08/2020 00:00:00  
EXCHANGE      Security Update  KB4570332     NT AUTHORITY\SYSTEM  11/09/2020 00:00:00  
EXCHANGE      Security Update  KB4577667     NT AUTHORITY\SYSTEM  14/10/2020 00:00:00  
EXCHANGE      Security Update  KB4580325     NT AUTHORITY\SYSTEM  14/10/2020 00:00:00  
EXCHANGE      Security Update  KB4577668     NT AUTHORITY\SYSTEM  14/10/2020 00:00:00  
EXCHANGE      Security Update  KB4587735     NT AUTHORITY\SYSTEM  16/11/2020 00:00:00  
EXCHANGE      Security Update  KB4512937     YTW\Roxxxxx             11/01/2021 00:00:00  
EXCHANGE      Security Update  KB4598480     NT AUTHORITY\SYSTEM  31/01/2021 00:00:00  
EXCHANGE      Security Update  KB4535680     NT AUTHORITY\SYSTEM  31/01/2021 00:00:00  
EXCHANGE      Security Update  KB4601393     NT AUTHORITY\SYSTEM  17/02/2021 00:00:00  
EXCHANGE      Update           KB4577586     NT AUTHORITY\SYSTEM  17/02/2021 00:00:00  
EXCHANGE      Update           KB4601555     NT AUTHORITY\SYSTEM  17/02/2021 00:00:00  
EXCHANGE      Update           KB4589208     NT AUTHORITY\SYSTEM  11/03/2021 00:00:00  
EXCHANGE      Security Update  KB5000859     NT AUTHORITY\SYSTEM  11/03/2021 00:00:00  
  

Answer 1

Found a fix - put Carbon Black in bypass mode then install.