Active Directory Replication Risk: Schema Master on Windows Server 2025 During Exchange Updates

Flowchart showing how Windows Server 2025 Schema Master causes Active Directory replication issues during Exchange CU schema update and steps to fix it

📌 Introduction When planning or applying Exchange cumulative updates (CUs) — such as Exchange 2019 CU15 or Exchange SE RTM — there is a significant but often overlooked risk that can disrupt your on‑premises Active Directory replication. This issue specifically arises when the Schema Master FSMO role is held by a Windows Server 2025 domain controller. … Read more