A subtle but dangerous bug in Windows Server 2025’s Schema Master FSMO role is causing duplicate schema entries that can break Active Directory replication and trigger schema-mismatch errors on older domain controllers — the issue is being discussed by administrators and reported in the field...
active directory
ad replication
adprep
adsiedit
backup and recovery
domain controllers
event id 1203
exchange schema
field reports
fsmo roles
ldifde
microsoft support
migration planning
release health
replication issues
schema master
schema mismatch
troubleshooting
windows server 2025
