Microsoft Exchange Server 2019 CU11 or CU12 - Mailbox Server role isn't installed on this computer

JOE TAM 46 Reputation points

Dear Sir,

 Customer has an Exchange 2019 Server installed with CU10 update 5 (KB5012698), when the server insert the CU11 ISO file to upgrade, error message occurred.


The Mailbox Server role isn't installed on this computer


Global updates need to be made to active directory, and this user account isn't member of the enterprise admins group.

This user account is the default domain administrator ID.

Please suggest.

Joe Tam

Exchange Server
Exchange Server
A family of Microsoft client/server messaging and collaboration software.
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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. Xuyan Ding - MSFT 6,496 Reputation points Microsoft Vendor

    Hi @JOE TAM ,

    • First confirm with you whether the DC in the same site as the Exchange server is the schema master?Please check via SetupAssist script.
    • If not, The schema, AD and domains can be prepared directly in the site where the schema master resides.
    • Or you can move the role to the current site's server. Then run the /PrepareSchema, /PrepareAD, and /PrepareDomains commands from the command prompt and wait for AD replication to complete.

    Note that your account needs to be a member of the Schema Admins and Enterprise Admins security groups to prepare the schema.

    Please follow the steps in the article: Prepare Active Directory and domains for Exchange Server.

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