There is a lot of great documentation on Exchange Online migrations. The issue can be knowing where to start. This blog post is a consolidation of information and aims to help you understand various ...
Updated Mar 20, 2024
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Hi everyone,
hope, someone can give me an answer or maybe just a tip.
I try to migrate a customer to EXO. Customer has 2 local domains. Each domain with its own Exchange (different mail-domains).Trust between Forests is established. Main branch, customer.com is synced to entra, hybrid is configured, migration is possible.
Second domain "customer-holding.com" has to be migrated into the same tenant. My first guess was to do a cutover for the second Domain. Users from this domain are not synced to entra right now, so i thought, CutOver would be possible. But when i try to create a batch, i allways get the error "Directory Synchronisation is enabled for tenant.onmicrosoft.com". Yes, it is enabled and Users are synced from "customer.com" but no User is synced from the second domain. Do i have to disable snyc completely to do a cutover? Are there other options i can use? we just need to move Mailboxes from the second Domains Exchange to the cloud. Hope anyone can help. Thanks!
https://learn.microsoft.com/en-us/entra/identity/hybrid/connect/plan-connect-topologies#multiple-forests-single-microsoft-entra-tenant