Understanding Retention Tags and Retention Policies

Applies to: Exchange Server 2010

Topic Last Modified: 2010-02-01

Messaging records management (MRM) is the records management technology in Microsoft Exchange Server 2010 that helps organizations to reduce legal risks associated with e-mail and other communications. MRM makes it easier to keep messages that are needed to comply with company policy, government regulations, or legal needs, and to remove content that has no legal or business value.

Organizations formulate MRM policies that specify the retention period for different classes of e-mail messages. However, in the past, enforcing those policies has often been challenging. Attempts to automate the MRM process have met with limited success. The MRM functionality in Exchange 2010 addresses these challenges.

Looking for management tasks related to MRM? See Deploying Messaging Records Management.


Messaging Records Management Strategy

Retention Tags

Retention Policies

Retention Hold

MRM in Exchange 2010 is accomplished by using retention tags and retention policies. Before discussing the details about each of these retention features, it's important to learn how the features are used in the overall Exchange 2010 MRM strategy. This strategy is based on:

  • Assigning retention policy tags (RPTs) to default folders, such as the Inbox.
  • Applying a default policy tag (DPT) to mailboxes to manage the retention of all untagged items.
  • Allowing the user to assign personal tags to custom folders and individual items.
  • Separating MRM functionality from users' Inbox management and filing habits. Users aren't required to file messages in managed folders based on retention requirements. Individual messages can have a different retention tag than the one applied to the folder in which they're located.

The following figure illustrates the tasks involved in implementing this strategy.

Using Retention Policies for Messaging Retention

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As illustrated in the preceding figure, retention tags are used to apply retention settings to folders and individual items such as messages, notes, and contacts. These settings specify how long a message remains in a mailbox and the action to be taken when the message reaches the specified retention age. When a message reaches its retention age, it's moved to the personal archive, deleted, or flagged for user attention.

Unlike managed folders (the MRM feature introduced in Exchange 2007), retention tags allow users to tag mailbox folders and individual items for retention. Users no longer have to file items in managed folders based on message retention requirements.

Managed folders are still available in Exchange 2010. To learn more, see Understanding Managed Folders.

There are three types of retention tags:

  • Retention policy tags (RPTs)   RPTs apply retention settings to default folders such as Inbox, Deleted Items, and Sent Items. Mailbox items in a default folder that have an RPT applied inherit the folder's tag. Although users can't apply a different tag to a default folder, they can apply a different tag to the items in a default folder.
    You can create RPTs for the following default folders:
    • Deleted Items
    • Drafts
    • Inbox
    • Junk E-mail
    • Outbox
    • Sent Items
    • RSS Feeds
    • Sync Issues
    • Conversation History
    You can't include more than one RPT for the same default folder type in one retention policy. For example, if a retention policy has an Inbox tag, you can't add another RPT of type Inbox to that retention policy.
    In Exchange 2010, RPTs aren't supported for the Calendar, Contacts, Journal, Notes, and Tasks default folders.
  • Default policy tags (DPTs)   DPTs apply retention settings to untagged mailbox items. Untagged items are mailbox items that don't already have a retention tag applied, either by inheritance from the folder in which they're located or by the user. A retention policy can't contain more than one DPT.
  • Personal tags   Personal tags are available to Outlook 2010 and Outlook Web App users as part of their retention policy. Users can apply personal tags to folders they create or to individual items, even if those items already have a different tag applied.

You can select from one of the following actions to specify what retention action should apply to a mailbox item when it reaches its retention age:

  • MoveToArchive   The MoveToArchive action moves a message to the user's archive mailbox. Messages are moved to a folder in the archive mailbox that has the same name as the source folder in the user's primary mailbox. This allows users to more easily find messages in their archive mailbox. To learn more about archive mailboxes, see Understanding Personal Archives.
  • MoveToDeletedItems   The MoveToDeletedItems action moves messages to the Deleted Items folder. This emulates the behavior experienced by users when they delete a message. Items in the Deleted Items folder can be moved back to the Inbox or any other mailbox folder. Depending on the user's mailbox settings in Outlook or Outlook Web App, the Deleted Items folder may be emptied when the user logs off Outlook Web App or closes Outlook. You can also create an RPT for the Deleted Items folder to take the required action after a specified period.
  • DeleteAndAllowRecovery   The DeleteAndAllowRecovery action emulates the behavior when the Deleted Items folder is emptied or the user hard deletes a message. When this happens, and deleted item retention is configured for the mailbox database or the user, messages move to the Recoverable Items folder. The Recoverable Items folder (also known as the dumpster) provides the user another chance to recover deleted messages. To do so, the user would access the Recover Deleted Items dialog box in Outlook 2010 or Outlook Web App. To learn more about recoverable items, see Understanding Recoverable Items.
  • PermanentlyDelete   The PermanentlyDelete action permanently deletes a message. When this action is applied to a message, it's purged from the mailbox. This action is like a deleted message being removed from the Recoverable Items folder. After this happens, the user can no longer recover the message.
    If legal hold is enabled for a mailbox user, Multi-Mailbox Search will still return permanently deleted messages in search results. To learn more, see Understanding Multi-Mailbox Search.
  • MarkAsPastRetentionLimit   The MarkAsPastRetentionLimit action marks a message as past the retention limit. Supported Outlook clients (Outlook 2010 and Office Outlook 2007) use strikethrough text when displaying messages that are past their retention limit. The strikethrough text will notify users that the message is expired. As a result, they can take further action, such as deleting the message or moving it to the archive mailbox. This action can help create awareness about the MRM functionality in your organization.

For details about how to create retention tags, see Create a Retention Tag.

You can use retention policies to group one or more retention tags and apply them to mailboxes. A mailbox can't have more than one retention policy. Retention tags can be linked or unlinked from a retention policy at any time.

A retention policy can have the following retention tags:

  • One or more RPTs for supported default folders.
    You can't link more than one RPT for a particular default folder (such as Deleted Items) to the same retention policy.
  • One DPT of type All.
  • Any number of personal tags.

Although you can add any number of personal tags to a retention policy, having many personal tags with different retention settings can confuse users. We recommend linking no more than 10 personal tags to a retention policy.

Although a retention policy doesn't need to have any retention tags linked to it, we don't recommend using this scenario. Mailboxes with a retention policy that doesn't have any retention tags linked to it may cause mailbox items to never expire.

For details about how to create a retention policy, see Create a Retention Policy.

For details about how to apply a retention policy to mailboxes, see Apply a Retention Policy to Mailboxes.

The Managed Folder Assistant runs on Mailbox servers and processes mailboxes that have a retention policy applied. The assistant applies the retention policy by inspecting items in the mailbox and determining whether they are subject to retention. It then stamps items that are subject to retention with the appropriate retention tags and takes the specified retention action on items that are past their retention age.

The Managed Folder Assistant runs on a specified schedule. By default, it's scheduled to run daily from 01:00 to 04:00 (1:00 A.M. to 4:00 A.M.). You can schedule the assistant to run at a time when the Mailbox server is relatively idle or not under a heavy load. When determining a schedule for the assistant, consider other processes that compete for Mailbox server resources, such as offline defragmentation of the mailbox database and antivirus scans.

The Managed Folder Assistant doesn't take any action on messages that aren't subject to retention, specified by setting the retention tag's RetentionEnabled property to false. You can also set this property to false to temporarily suspend items with a particular tag from being processed.

For details about how to schedule the Managed Folder Assistant, see Schedule the Managed Folder Assistant.

Default folders such as Inbox, Deleted Items, and Sent Items get RPTs applied as specified in the retention policy. Users can't change the RPTs associated with default folders. However, a user can apply a personal tag to an item in a default folder, causing the item to have a different retention setting than the folder in which it resides. Similarly, a user can also assign one personal tag to a user-created folder, but a different personal tag to an item in that folder.

A mailbox item moved from one folder to another inherits any tags applied to the folder to which it's moved. If an item is moved to a folder that doesn't have a tag assigned, the default policy tag is applied to it. If the item has a tag explicitly assigned to it, the tag always takes precedence over any folder-level tags or the default tag.

When a retention tag is removed from the retention policy applied to a mailbox, the tag is no longer available to the user and can't be applied to items in the mailbox.

Existing items that have been stamped with that tag continue to be processed by the Managed Folder Assistant based on those settings and any retention action specified in the tag is applied to those messages.

However, if you delete the tag by using the Remove-RetentionPolicyTag cmdlet, the tag definition stored in Active Directory is removed. The next time the Managed Folder Assistant runs, it processes all items that have the removed tag applied and restamps them. Depending on the number of mailboxes and messages, this process may significantly consume resources on all Mailbox servers that contain mailboxes with retention policies that include the removed tag.

If a retention tag is removed from a retention policy, any existing mailbox items with the tag applied will continue to expire based on the tag's settings. To prevent the tag's settings from being applied to any items, you should delete the tag. Deleting a tag removes it from any retention policies in which it's included.

You can disable retention for a retention tag. If you do this, the Managed Folder Assistant ignores items that have that tag applied. Items that have a retention tag for which retention is disabled never expire. Because these items are still considered tagged items, the DPT doesn't apply to them. For example, if you want to troubleshoot retention tag settings, you can temporarily disable a retention tag to stop the Managed Folder Assistant from processing messages with that tag.

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When users are temporarily away from work and don't have access to their e-mail, retention settings can be applied to new messages before they return to work or access their e-mail. Depending on the retention policy, messages may be deleted or moved to the user's personal archive. You can temporarily suspend retention policies from processing a mailbox for a specified period by placing the mailbox on retention hold. When you place a mailbox on retention hold, you can also specify a retention comment that informs the mailbox user (or another user authorized to access the mailbox) about the retention hold, including when the hold is scheduled to begin and end. Retention comments are displayed in supported Outlook clients. You can also localize the retention hold comment in the user's preferred language.

Placing a mailbox on retention hold doesn't affect how mailbox storage quotas are processed. Depending on the mailbox usage and applicable mailbox quotas, consider temporarily increasing the mailbox storage quota for users when they're on vacation or don't have access to e-mail for an extended period. For more information about mailbox storage quotas, see Configure Storage Quotas for a Mailbox.

During long absences from work, users may accrue a large amount of e-mail. Depending on the volume of e-mail and the length of absence, it may take these users several weeks or more to sort through their messages. In these cases, consider the additional time it may take the users to catch up on their mail before removing them from retention hold.

If your organization has never implemented MRM and your users aren't familiar with its features, you can also use retention holds during the initial phase of your MRM deployment.

For details about how to place a mailbox on retention hold, see Place a Mailbox on Retention Hold.

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