How Retention Age is Calculated

 

Applies to: Exchange Server 2010 SP2, Exchange Server 2010 SP3

If you set a retention limit on items that have a retention tag or are within a managed folder, the Managed Folder Assistant tests the age of those items, and takes the specified action for items that have exceeded their retention limit.

Determining the Age of Different Types of Items

For mailboxes that use retention policies, the retention age of mailbox items is calculated from the date of delivery. When the Managed Folder Assistant processes items in a mailbox, it stamps a start date and an expiration date for all items that have retention tags with the Delete and Allow Recovery or Permanently Delete retention action. Items that have an archive tag are also stamped with a move date.

In Microsoft Exchange Server 2010 Service Pack 1 (SP1), the retention age for items in the Deleted Items default folder is calculated based on the date of delivery unless the item was moved or deleted from a folder that doesn't have an inherited or implicit retention tag. Consider the following examples:

• A user receives a message in the Inbox folder on 01/26/2011. The Inbox folder has a retention tag configured to delete items in 365 days.

  1. The Managed Folder Assistant processes the message. It stamps the message with a start date of 01/26/2011 and an expiration date of 01/26/2012.

  2. The user soft-deletes the item on 02/27/2011.The item is moved to the Deleted Items folder, which has a retention tag configured to delete the item in 30 days.

  3. The Managed Folder Assistant processes the message. It recalculates the expiration date based on the start date (01/26/2011).

  4. Because the item is older than 30 days, it is deleted immediately.

• A user receives an item in the Inbox folder on 01/26/2011. The Inbox folder doesn't have a retention tag applied, and the retention policy doesn't contain a default policy tag.

  1. The user soft-deletes the item on 02/27/2011. The item is moved to the Deleted Items folder, which has a retention tag configured to delete items in 30 days.

  2. The Managed Folder Assistant processes the mailbox on 03/27/2011, and determines that the item doesn't have a start date. It stamps the current date as the start date and 04/27/2011 as the expiration date.

  3. The item is deleted on 04/27/2011, which is 30 days after it was deleted or moved to the Deleted Items folder.

The same conditions are true for both move tags (tags that have the Move to Archive retention action) and delete tags (tags that have the Delete and Allow Recovery and Permanently Delete retention actions).

Important

Retention tags include retention settings such as retention age and retention action. However, to configure retention settings for a managed folder, you must create managed content settings for it. An Exchange Server 2010 mailbox can be configured to use either a retention policy or a managed folder mailbox policy.

When you create managed content settings for a managed folder, you can select one of the following options to specify how the Managed Folder Assistant determines when a retention period starts:

• When the item is delivered to the user's mailbox (or for calendar items and recurring tasks, when the item is older than its end date)

• When the user moves the item into the managed folder

After determining when a retention period starts, the Managed Folder Assistant uses rules to determine the age of items for the purpose of enforcing retention limits. The following tables describe the rules used for various items.

Calendar Items

Depending on whether a calendar item is in the Deleted Items folder, the Managed Folder Assistant uses the following rules to calculate the age of calendar items and enforce retention limits. The steps for each rule are listed in the order in which they are performed.

Location of calendar items	Rules
Calendar items in the Deleted Items folder	A calendar item expires according to its expiration date, if one exists. If a calendar item doesn't have an expiration date, it expires according to its new stamped date (its message-creation date plus retention days).
Calendar items not in the Deleted Items folder	Non-recurring calendar items expire according to their end date. Recurring calendar items expire according to the end date of their last occurrence. Recurring calendar items with no end date don't expire.

Tasks

Depending on whether a task is in the Deleted Items folder, the Managed Folder Assistant uses the rules listed in the following table to calculate the age of tasks and enforce retention limits. The steps for each rule are listed in the order in which they are performed.

Location of tasks	Rules
Tasks in the Deleted Items folder	A task expires according to its message-received date, if one exists. If a task doesn't have a message-received date, it expires according to its message-creation date. If a task has neither a message-received date nor a message-creation date, it doesn't expire.
Tasks not in the Deleted Items folder	Non-recurring tasks: A non-recurring task expires according to its message-received date, if one exists. If a non-recurring task doesn't have a message-received date, it expires according to its message-creation date. If a non-recurring task has neither a message-received date nor a message-creation date, it doesn't expire. A recurring task expires according to the end date of its last occurrence. If a recurring task doesn't have an end date, it doesn't expire. A regenerating task (which is a recurring task that regenerates a specified time after the preceding instance of the task is completed) doesn't expire.

Note

In Exchange 2010, retention tags aren't supported for the Calendar and Tasks default folders. The Managed Folder Assistant doesn't process items in these folders.

Other Items

For all other types of items, the Managed Folder Assistant uses the following rules to calculate the age and enforce retention limits. These items include:

• E-mail messages

• Documents

• Faxes

• Journal items

• Meeting requests, responses, and cancellations

• Missed calls

The steps for each rule are listed in the order in which they are performed.

Period at which retention starts	Rules
When an item is delivered to a user's mailbox	If the item has a message-received date, the message-received date is used. If the item doesn't have a message-received date, the message-creation date is used. If the item doesn't have a message-creation date, the message doesn't expire.
When a user moves the item to the managed folder	If the item has a move date, the move date is used. If the item doesn't have a move date, the item doesn't expire.

Corrupted Items

Any corrupted items in a mailbox are skipped by the Managed Folder Assistant, and they don't expire.

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