Migration from Microsoft Entra Connect Sync to Entra Cloud Sync

hi Ivane99​  It’s best not to manually disable the OUs right away. Instead, follow a phased approach using staging mode first:

Set up Cloud Sync in staging mode.

This lets you safely test synchronization — it reads your data but doesn’t export changes to Entra ID.

Validate everything.

Check that your users, groups, and attribute flows look correct in staging mode.

Uncheck those OUs in Connect Sync.

Once validated, disable those OUs in your existing Entra Connect configuration to avoid duplicate sync.

Turn off staging mode.

Cloud Sync will then start syncing those OUs for real.

This method avoids accidental deletions and ensures a smooth handoff between sync engines.

Also refer the site:

https://learn.microsoft.com/en-us/entra/identity/hybrid/cloud-sync/tutorial-pilot-aadc-aadccp