he “Tech Tip of the Week” focuses on Exchange Hybrid/Coexistence migrations to Office 365 with the new Wave 15 (Exchange 2013) backend.My “Tech Tip of the Week” focuses on Exchange Hybrid/Coexistence migrations to Office 365 with the new Wave 15 (Exchange 2013) backend.

If you are not aware, Microsoft released the new version of Office 365 (branded as “Wave 15”) about 1 month ago (Feb. 27, 2013) and there are some new wrinkles and challenges to be encountered as a result.  One in particular deals with Exchange Hybrid/Coexistence with this new Office 365 Wave 15.  This week’s tech tip will be short and sweet; however it will save you time when trying to decide how to architect the solution.

1.)  If you are dealing with any customers who have the new Wave 15 Office 365 tenants and want Exchange Hybrid, here are some things to consider when planning the architecture.

  • If the customer has an Exchange 2007 or Exchange 2010 on-premises environment, then you can install/setup/configure an Exchange 2013 Hybrid/Coexistence server in order to facilitate the migration and establish the coexistence.
  • If the customer has Exchange 2003, then you CANNOT use an Exchange 2013 Hybrid server.  This is because Exchange 2013 is incompatible and simply cannot coexist with Exchange 2003.  In this case, you MUST use an Exchange 2010 Hybrid/Coexistence server in order to facilitate this migration.

2.)  If you are indeed migrating a customer with an existing Exchange 2003 or SBS 2003 environment, then you must also perform a double-migration.  This means that you must first migrate the mailboxes to the Exchange 2010 Hybrid server, and THEN you can migrate the mailbox up to Office 365 Wave 15.  If you attempt to do a straight “New Remote Move Request” from a mailbox living on an Exchange 2003 server directly to Office 365 Wave 15, you WILL get errors and the mailbox migration will fail.

Most of the errors will cite corruption on most if not all of the items, and occasionally you will see different errors, but basically they occur because the Exchange 2013 servers within Office 365 Wave 15 simply cannot communicate properly with the Exchange 2003 servers/mailboxes.

So, if you have a customer with this scenario, make sure you plan the deployment of your Exchange 2010 Hybrid server accordingly.  Meaning, make sure you install the Mailbox server role upon installing Exchange 2010 and make sure that you have allocated enough disk space to the Exchange 2010 server to temporarily accommodate the mailboxes that will be living upon it during this double-migration.  You may also need to add some extra RAM/CPU to it so it can temporarily handle serving these mailboxes while its performing its typical hybrid tasks.

I hope you enjoyed Justin’s Tech Tip of the Week!

Apparently our blog post here regarding this double-hop migration situation when migrating from an Exchange 2003 on-premises environment to Office 365 Wave 15 reached a fever-pitch within Microsoft, as they cited this blog and have input a fix for this for new Office 365 Wave 15 subscriptions. 

This fix may be implemented to current Wave 15 clients, but it is a fix that has been applied to the build of the Office 365 Wave 15 template, so this should be no longer an issue for new O365 customers who choose to perform Exchange Hybrid/Coexistence migrations.

Basically, if you have customers in the middle of a migration using the double-hop method, have them keep doing this until their migration is complete.  Any new customers that you work with should no longer experience this; however it is always an available option just in case. 

–  Justin

To view any of my previous tips, see here:

Shared Mailboxes Part I -What to do if you want or need to convert a full (user) Office 365 mailbox into a Shared Mailbox.

Shared Mailboxes Part II – How do you create a shared mailbox from scratch and then add permissions to them?  

Justin’s Tech Tip of the Week – Office 365 Calendar Invites and Meeting Requests

Justin’s Tech Tip of the Week – Archive Mailboxes

Justin’s Tech Tip of the Week – Mail Retrievals within Office 365

How to use Microsoft Active Directory Synchronization (“MS DirSync”) for Office 365 more effectively