Dear All,

Last year, we migrated Exchange 2010 to Zimbra and found it was difficult to handle.

So we want to move back to Exchange 2013. Exchange 2013 and Zimbra may co-exist in our organization.

We will deploy two Exchange Server,CAS+Mailbox.

We are considering if put Exchange as the smarthost.

Anyone has idea?

Besides, is there any wonderful migration tool?

Xiu

More background informaiton...

We just powered off  the previous Exchange Server and removed.We did not uninstall it from the organization.So we have orphan information.

Hi ElenaNorge,

According to your description, I understand you want to migrate from Zimbra to Exchange 2013 and deploy co-existence environment.
If I misunderstand your concern, please do not hesitate to let me know.

I notice that you havent uninstall Exchange architecture from your environment, can you power on the previous Exchange 2010?
I find an article about your question, for your reference:
https://social.technet.microsoft.com/Forums/en-US/b85d4c49-2918-4dc3-80b7-87820f4e5ffa/zimbra-8-to-exchange-2013-migration-suggestions?forum=exchangesvrdeploy
exporting all data from Zimbra and importing them into new Exchange 2013 is the best way to performing such this migration

Besides, this may be related to Zimbra. Please contact the product provider so that you can get more professional suggestions.

Best Regards,
Allen Wang