Exchange Online Onboarding Message Size Limit Now 150 MB

Whenever administrators migrate mailboxes to Exchange Online, an onboarding limit in terms of message size always apply in order to avoid migrating huge messages and potentially impact service. Up until now this limit was 25MB (attachment size) plus overhead, so approximately 36MB in total. If a mailbox contained any emails over this size, they would simply be skipped and administrators had to find alternative ways to import them. To be honest, not many companied allow such big emails, but I have worked with a few that do, which would cause an issue if migrating to Office 365...

Now, this limit has been increased to 150MB (and is already available to all customers)! However, please have the following in mind:

• This new limit only applies to onboarding moves using the native Mailbox Replication Service (MRS) and which target AD user objects with a RecipientType of MailUser (MEU) that do not have MaxReceiveSize stamped. For example, hybrid deployments;
• All other data migration solutions, both using Microsoft tools and 3rd party tools target UserMailbox (MBX) AD users (i.e., rely on the mailbox already being created in Exchange Online). The increased onboarding message size limit does not apply to these solutions which will use the limit (MaxReceiveSize) configured on these MBX objects. The maximum-allowed onboarding message size limit for these solutions remains 36MB. This includes merges (staged and cutover migration), IMAP, EWS, MAPI, 3rd party tools, and PST Import.

The good news is that soon administrators will be able to customize the send/receive size limit, enabling them to modify the MaxSendSize and MaxReceiveSize limits on their MBXs and MEUs, effectively overcoming this limitations (hopefully).

The Exchange Online Service Description has now been updated to reflect this change.

Managing Exchange Online using Server 2012 R2 Essentials Experience Role

Windows Server 2012 Essentials and the Essentials Experience role build on the previous Office 365 Integration Module for Small Business Server 2011 Essentials. This option is now part of the core product (not a separate download) and provides a seamlessly integrated management experience on Essentials for customers who are using Exchange Online.

On top of the core feature set that was included in the Office 365 Integration Module for SBS 2011 Essentials, such as integrated user account management and automatic user password synchronization, Microsoft also made a few enhancements to make the experience better:

• Support for multiple e-mail addresses. Having multiple domains and/or assigning multiple e-mail addresses to a single user are common scenarios even for small businesses. Now it is finally possible to easily do that from within the Essentials’ Dashboard;
• Improved Office 365 domain configuration wizard. In the Office 365 Integration Module for SBS 2011 Essentials, administrators were required to configure Remote Web Access (RWA) when configuring a domain for Office 365, which caused a lot of confusion. For example, administrators had to provide an SSL certificate which was not actually needed by Office 365, but was required by RWA. Now these two have been de-coupled. Another improvement is the option to configure a different domain name for Office 365 and for RWA, allowing small businesses to continue to use the same free domain names like letsexchange.remotewebaccess.com for RWA on Essentials and a different domain name for e-mail in Office 365;
• Display mailbox usage information. The Office 365 tab on the Essentials Dashboard now shows the mailbox usage information.

To read the full article, please check my Managing Exchange Online using Server 2012 R2 Essentials Experience Role article series on MSExchange.org.