Exchange Servver Update to CU21 fails

Remtek 96 Reputation points

I completed the ADprep and started the update to CU21
Everything seem to be going fine but then I started getting errors
The process fails while step:
Mailbox role: Transport
Microsoft ExchangeServiceHost will not start.

Unable to start most of the MsExchnage Services
Web UI does not start at all.

Also getting tons of Event ID 2280 errorw:
The Module DLL C:\Program Files\Microsoft\Exchange Server\V15\Bin\kerbauth.dll failed to load. The data is the error.

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Remtek 96 Reputation points

    The problem was fixed by copying the application files from the CU21 Source ISO to the common folder in the installation path on the server.
    It seems that during the update process not all files were copied. The Microsoft Exchange Active Directory Service could not start because it was trying to use the service file from the previous CU version.
    Once the correct files from CU21 was copied over all of the services were able to start and the update completed without any further problems.
    Once the update was complete a reboot was needed. After reboot I applied the latest security update for CU21 and then everything started working again.

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  1. Remtek 96 Reputation points


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  2. Jade Liang-MSFT 9,971 Reputation points Microsoft Employee

    Hi @Remtek ,

    I understand that you are facing with cannot start some services on computer when you update exchange server. As I know, it may occur when your services were disabled and couldn’t be set to “automatic” during the updating, in this case, it’s recommended to follow this document to check if your services were disabled and set them to automatic for testing .

    If the issue still exists after that, based on my research, I found a similar thread that mentioned the version of Unified Communications Managed API 5.0 may affect it, if you are also working with UCMA 5.0, please try to uninstall it and install version UCMA 4.0 to check.

    Also getting tons of Event ID 2280 error:

    For this error, as I know, it may occur when the path of kerbauth.dll is different from the latest path where exchange has been installed, if it’s your case, it’s recommended to change the path manually to resolve it, for more information, please refer to this document: The Module DLL kerbauth.dll failed to load. The data is the error. (The Module DLL C:Program FilesMicrosoftExchange ServerV14Binkerbauth.dll failed to load. The data is the error.)(Please note the location is V15 for Exchange 2016).

    Hope that would be helpful to you.

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