By Greg Smith

Before Making the Leap

Many organizations making the leap to Office 365 for their business services also choose to migrate their legacy data. Whether from existing mail systems or third-party archiving systems, they find little objection to migrating archives to Office 365 because the excessive data storage costs nothing. In addition, Microsoft provides eDiscovery tools around that data, depending on licensing.

Before you make the leap, take the time to understand the facts about archives and the way Office 365 handles data.

Traditionally, organizations wishing to retain older emails for eDiscovery and free up space from their taxed local mail systems, deployed a third-party archiving solution. Several vendors, including Veritas, EMC and HP provide solutions that accommodate these organizational needs. But depending on the need, they store the data differently.


For organizations wishing to capture all email correspondence and conduct eDiscovery, they typically supported a function called Journaling. Journaling forwards a copy of every message sent or received in the source email system to the archive.

Not stored by message owner, journaled emails simply resided in a huge repository. The solution indexes their content to provide auditors with the ability to search for pertinent information across all messages.

Mailbox Archiving and Message Stubbing

Many organizations seek to manage the size of their message stores on their local email system. In this case, archiving products conduct mailbox archiving and message stubbing. Mailbox archiving takes messages directly from the users’ mailbox and stores them on the archival system by owner.

In some cases, message stubs or links connect the message in the users’ mailbox with the archived content to reduce storage overhead. This archiving approach also provides full eDiscovery, but typically facilitates space management in systems that provide both options.

Third-party archive solutions support one method or the other, or sometimes both methods. The critical fact to understand when moving to Office 365 is that the Office 365 Archiving solution supports only Mailbox Archiving.

Every archive gets assigned to a specific user account and contains all the archived email created or sent by that user. Therefore, the source data must match this format.

Migrating Archives to Office 365

Migrating Archives to Office 365 Decisions

Organizations looking to migrate their archived data to Office 365, face at least three questions and some decisions:

Journaled Data

1)  If my archive solution contains journaled data, then all messages exist as forwarded attachments. So, how can I convert those attachments back to messages sorted by individual owner?

While you could migrate journaled mail back into a single Office 365 account, this practice is not endorsed by Microsoft. They do not allow systems to journal to Office 365. Nor does the license agreement allow for storage of multi-user messages within the archive.

In addition, creating a Journal account would require the organization to search this account with each eDiscovery request. And data could not easily be subject to any accurate retention or destruction policy.

Fortunately, Messaging Architects maintains the right tools to convert journaled messages back into their original format. The conversion process supplies each message with the correct sender and recipient addresses. This prepares them to be assigned and migrated into the correct user archive in Office 365.

One thing to note is that some or all the journaled messages to be migrated to Office 365 may already exist. Stored as copies instead of physically archived messages, many old and deleted messages suddenly appear in a user’s Office 365 archive, confusing users.

When migrating, select a solution with the option to migrate directly to the Recoverable Items folder of Office 365. This ensures that older data is present for eDiscovery but not unexpectedly visible to the user.

Stubbed Messages

2)  If I have stubbed messages, how will those messages be migrated and accessed in Office 365?

Much like a URL link in an email, a message stub when clicked opens the message from the system on which it resides.

In most cases this means that the archiving system must remain functional. And it would have to be accessible to the Public network if you wished to maintain access to those messages, even from Outlook on Web from outside your office.

Messaging Architects helps organizations that created stubbed messages by rehydrating those messages back into Exchange. Then, they can be migrated in their entirety to Office 365, thus eliminating any dependencies on the local archive system.

Inactive Accounts

3)  How do I handle the large number of inactive accounts in my archival system?

This is always a tough question. Microsoft provides excellent incentives to move your obsolete and inactive user data to the cloud because they do not charge the organization to store that data…. YET!

Organizations enjoy essentially two options for preserving inactive user data—User Accounts with Retention Policies or Shared User Accounts.

User Accounts with Retention Policies

Microsoft Office 365 allows for the application of litigation hold policies and retention policies to active accounts. When these accounts expire or become deleted, the policies direct the system to retain the data even without a license.

In this way, organizations simply create user accounts for inactive accounts and transfer the data. Then they put those accounts on retention or litigation hold and remove the license to preserve the data indefinitely.

These accounts can be fully accessed and searched by those in compliance and legal roles. This assumes an E3 or equivalent license level applied at the time of the data migration and policy application.

Since these accounts remain unlicensed, data cannot be shared with regular users through delegate rights. Thus, the data becomes accessible only to eDiscovery roles.

Shared User Accounts

A shared user account is defined as an account owned and managed by another licensed user. Typically used as a generic account, it does not require a license. A limit of 50GB applies to the account mailbox.

The data in the account can be shared with other users through delegate rights. But Shared User Accounts are NOT subject to any retention or legal hold policies. To be able to search them or include them in eDiscovery would require a valid eDiscovery license applied to the account.

Migrating Archives to Office 365

Migrating Archives to Office 365 Successfully

Organizations migrating third party archives and legacy email from inactive accounts seek to do so without ongoing problems. Hence, they should fully understand and explore the requirements of the organization with respect to information retention and access.

In addition, they need to fully consider the various ways the data maps to the archiving and retention structures of Office 365. Fortunately, Messaging Architects Office 365 migration experts provide the assistance necessary to complete your migration efficiently and successfully.

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