Tenant wide default

Tenant-wide default

The Organization tab runs:

Set-OrganizationConfig -ExchangeAttributesCloudManagedByDefault

or

Set-OrganizationConfig -ExchangeAttributesServerManagedByDefault

What enabling does

New users synced from AD arrive in Entra without Exchange attributes. After you assign an Exchange Online license, the mailbox is created already cloud-managed. This is the end state when you want to retire the last Exchange Server.

Warning

Do not enable this while you still create mailboxes on-premises. A mailbox created in AD after the default is enabled does not appear in the Exchange Online GAL, and fixing that requires Microsoft Support.

The tool shows this warning and asks you to type ENABLE before it proceeds.

Disabling

Set-OrganizationConfig -ExchangeAttributesServerManagedByDefault changes the default for future users. It does not clear IsExchangeCloudManaged from users already affected. For those, contact Microsoft Support.