Released: September 2021 Quarterly Exchange Updates

Hi Exchange Team,

I'm trying to upgrade my test environment from Exch2016 CU21 + SU1 to Exch2016 CU22. My normal approach is to run it from an elevated cmd prompt but every single time I've tried to run the installer on the first server it's thrown the "there's a reboot pending" exception.

C:\Windows\system32>f:\setup.exe /m:Upgrade /IAcceptExchangeServerLicenseTerms_DiagnosticDataON

Microsoft Exchange Server 2016 Cumulative Update 22 Unattended Setup

Copying Files...
File copy complete. Setup will now collect additional information needed for installation.

Languages
Management tools
Mailbox role: Transport service
Mailbox role: Client Access service
Mailbox role: Unified Messaging service
Mailbox role: Mailbox service
Mailbox role: Front End Transport service
Mailbox role: Client Access Front End service

Performing Microsoft Exchange Server Prerequisite Check

    Configuring Prerequisites                                                                         COMPLETED
    Prerequisite Analysis                                                                             FAILED

There is a pending reboot from a previous installation of a Windows Server role or feature. Please restart the computer
and then run Setup again.
For more information, visit: http://technet.microsoft.com/library(EXCHG.150)/ms.exch.setupreadiness.PendingRebootWindowsComponents.aspx


The Exchange Server setup operation didn't complete. More details can be found in ExchangeSetup.log located in the
<SystemDrive>:\ExchangeSetupLogs folder.

I've restarted the server 5 times and it's thrown the same thing every time, I checked the setup log and it doesn't seem like this is actually the case:

[09/30/2021 10:58:27.0938] [1] Started [Rule:PendingRebootWindowsComponents] [Parent:RootAnalysisMember] [RuleType:Error]
[09/30/2021 10:58:27.0998] [1] Evaluated [Rule:PendingRebootWindowsComponents] [HasException:False] [Value:"True"] [ParentValue:"<NULL>"] [Thread:17] [Duration:00:00:00.0570024]
[09/30/2021 10:58:28.0000] [1] Finished [Rule:PendingRebootWindowsComponents] [Duration:00:00:00.0610040]

Just on the off chance that it was something related to the unattended installer I've tried launching the upgrade through the GUI setup and it is now successfully performing the upgrade. Underlying OS is fully-patched WinSvr2016.