Understanding how and when mailbox manager processes items

This article discusses the expected behavior of the Exchange Server Mailbox Manager service in different settings and with different target item locations. The Mailbox Manager service processes items according to the age limit, item location, and deletion mode that are selected. The service either deletes or moves items that reach specified age limits for the location of those items. This article assumes that the Run Mode is set to Cleanup rather than Audit on the General tab of the Mailbox Manager add-in properties.

The Mailbox Manager service is included with Exchange Server Service Pack 4, either on the CD-ROM in the Support\Mbmngr folder, or in the Sp4_55ss.exe file that is available from the following Web site: Note that the Mailbox Manager service requires Exchange Server 5.5 Service Pack 2 or later. See the Mailbox Manager documentation for complete system requirements.

How Mailbox Manager Processes Items

Mailbox Manager processes items according to the Deletion Mode that is selected on the General tab of the Exchange Server add-in object properties. If Mailbox Manager is enabled for a folder in the Folder Age Limits dialog box and an item in that folder exceeds the age limit that is specified in that dialog box, that item is "processed." Mailbox Manager can move an item to the Deleted Items folder or to a corresponding subfolder in the System Cleanup folders, or Mailbox Manager can "hard delete" an item immediately. The following are available Deletion Mode settings and explanations of these settings:

• Move to Deleted Items. This deletion mode simply moves the processed item to the Deleted Items folder.
• Move to System Cleanup Folders. This deletion mode creates subfolders in the System Cleanup folders that correspond to the processed items. The System Cleanup folders are created at the root of each user's mailbox at the same hierarchical level as the Inbox folder.
• Delete Items Immediately. This deletion mode performs a "hard delete" on processed items. For more information about how to recover these items, click the following article number to view the article in the Microsoft Knowledge Base:
  178630  (http://support.microsoft.com/kb/178630/ ) How to use Exchange Server 5.5 or Exchange 2000 Server to recover items that are not first transferred to the Deleted Items folder in Outlook

The exception to these explanations is the Deleted Items hierarchy. Mailbox Manager handles items in the Deleted Items hierarchy differently than items in other folders. Mailbox Manager never moves items in the Deleted Items folder or any of its subfolders to the System Cleanup folders or back to the Deleted Items folder. Instead, when Mailbox Manager processes an item in the Deleted Items folder, that item is deleted immediately.

When Mailbox Manager Processes Items

Mailbox Manager processes an item if the age of the item has reached the age limit that is specified in the Folder Age Limits dialog box for the folder in which the item is contained.

The age of an item is determined by the amount of time that has elapsed since the item was sent to the mailbox, and not by the amount of time that an item has spent in a particular folder. As a result, the System Cleanup folders need to have an age limit that is greater that all of the other folders.

For example, if the Inbox folder has a 10-day limit, and System Cleanup folder has a 15-day limit, after an item is in the Inbox folder for 10 days, Mailbox Manager moves the item to the System Cleanup folder. The item stays in the System Cleanup folder for 15 days before Mailbox Manager deletes the item. This is because the PR_LAST_MODIFICATION_TIME of the item is reset when the item is moved to the System Cleanup folder. The total retention time is the time that the item is kept in the original folder in addition to the time that the item is in the System Cleanup folder. In this scenario, the item stays in the original folder for 10 days and in the System Cleanup folder for 15 days for a total of 25 days.

IMPORTANT: Note that items that are in the subfolders of any folder that is listed in the Folder Age Limits dialog box (for example, subfolders of the Inbox, Sent Items, or Calendar folders) are processed when they reach the age limits that are set for Other Folders.

Quick Reference Tables

The following table outlines the way that an item is processed according to the location of the item and the deletion mode that is selected for the item. To find out the way that an item is processed, find the deletion mode in the column headings, and then find the item location in the row headings; the intersection is the action that is performed on the item during processing. The following table contains the age limit settings that applies to items in given locations. Each row contains an age limit that determines when an item is processed and an item location.