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Clarify /PrepareAD Requirement for Exchange Server SE RTM Upgrade

Köhler, Michael 20 Reputation points
2025-11-06T08:47:44.5533333+00:00

I recently performed an in-place upgrade from Exchange Server 2019 CU15 to Exchange Server Subscription Edition (SE) RTM, following the official documentation. The upgrade completed successfully, and I noted that the documentation does not mention the need to run /PrepareAD as part of this process.

However, in a lab environment, I ran /PrepareAD after the upgrade and observed that it updated the msExchProductID in the Configuration Partition to reflect the correct SE build version (15.02.2562.017). This behavior is not currently documented, and it raises some questions about whether /PrepareAD is optional, recommended, or unnecessary in this specific upgrade scenario.

In the production infrastructure this ID is still related to Exchange 2019 CU15: 15.02.1748.010, although every server was updates to Exchange SE RTM.

To improve clarity for administrators and ensure consistent Active Directory metadata across environments, I would like to suggest the following enhancements to the documentation:

  • Explicitly state that /PrepareAD is not required when upgrading from Exchange 2019 CU15 to SE RTM.
  • Clarify that /PrepareAD does update certain configuration metadata (e.g., msExchProductID), even if no schema changes are introduced.
  • Reiterate the distinction between /PrepareSchema and /PrepareAD, as they serve different purposes and are often misunderstood.

This clarification would be especially helpful for environments where AD metadata is monitored for compliance or automation purposes.

Thank you for your continued support and excellent documentation.

Exchange | Exchange Server | Other
Exchange | Exchange Server | Other
A robust email, calendaring, and collaboration platform developed by Microsoft, designed for enterprise-level communication and data management.Miscellaneous topics that do not fit into specific categories.
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  1. Hin-V 8,605 Reputation points Microsoft External Staff Moderator
    2025-11-06T09:23:02.6466667+00:00

    Hi @Köhler, Michael

    Thank you for posting your question in Microsoft Q&A, and for sharing such detailed observations from both your production and lab environments. This kind of feedback is incredibly valuable for refining documentation and improving upgrade processes. 

    According to official Microsoft guidance, the in-place upgrade from Exchange Server 2019 CU15 to Exchange Server Subscription Edition (SE) RTM is designed to be seamless. SE builds upon the 2019 codebase and does not introduce new schema extensions, which is why Active Directory preparation steps such as /PrepareAD or /PrepareSchema are not required. The schema version and organization object version remain unchanged between CU15 and SE RTM, which aligns with the documentation’s omission of these steps. 

    That said, your lab findings are insightful. Running /PrepareAD post-upgrade does update certain metadata, such as build-specific attributes, within the configuration partition. This behavior is expected: while /PrepareAD doesn’t modify the schema (that’s handled exclusively by /PrepareSchema), it can refresh the Exchange organization container and align version strings or other non-schema elements. This kind of update may be beneficial in environments where AD metadata consistency is important for monitoring, compliance, or automation. However, as your production experience confirms, it’s not required for functionality, the servers will operate correctly without it. 

    Regarding your suggestion, if you'd like to propose these enhancements directly, I recommend sharing your thoughts via the Tech Community forums, where product team members are actively engaged.

    Thank you once again for sharing this valuable insight and for contributing to the continued growth of our community. 

    If you have any additional concerns, feel free to comment below. I would be more than happy to assist. 

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  1. Andy David - MVP 159.7K Reputation points MVP Volunteer Moderator
    2025-11-06T10:39:01.1766667+00:00

    Those steps are automatically run if you have the permissions and your AD forest is a single domain:

    https://learn.microsoft.com/en-us/exchange/plan-and-deploy/prepare-ad-and-domains

    If they cant be run, the setup wizard will fail.

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