Background Cleanup for a mailbox store is non-default
[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at http://go.microsoft.com/fwlink/?linkid=34707.]
Topic Last Modified: 2010-07-28
The Microsoft® Exchange Best Practices Analyzer Tool reads the following registry entry to determine the current value data for the Background Cleanup registry value:
If the Analyzer tool finds that the value data for Background Cleanup is set to any value other than 60000 (decimal) or 0xEA60 (hexadecimal), a non-default configuration message is displayed. We recommend that you set the Background Cleanup value to the default value.
If the Background Cleanup value is set too high, the background cleanup process may not run frequently enough. Additionally, several problems may occur. These include the following:
Move mailbox may fail, and an event 1205 together with error code 0x4e3 may be logged.
Folder sizes and item counts that appear in Exchange System Manager or in Exchange Management Console may differ greatly from those that appear in Microsoft Outlook®. Additionally, database space that is occupied by these items may not be reclaimed.
Unread receipts for items that were deleted without being read may not be generated under certain circumstances.
Cleanup of old entries in the DeliveredTo table will not occur. The DeliveredTo table is used by the Exchange store to prevent the delivery of duplicate messages.
If the Background Cleanup value is set too low, the background cleanup process may cause unnecessary load on the server.
The following procedure reverts the Background Cleanup value to the default configuration from a value that is too high. Performing these steps can result in an increased load on the server until background cleanup has completed for all items that would typically have been cleaned up at the default interval. Therefore, we recommend that you make these changes at a time during which users will be minimally affected. Additionally, if messages for which read receipts were requested have been deleted without being read and have not been cleaned up because of this problem, unread receipts will be generated for each of those messages after you correct this problem.
This article contains information about how to edit the registry. Before you edit the registry, make sure that you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Registry Editor (Regedit.exe or Regedt32.exe).
To revert to the default configuration
Open Registry Editor.
Locate the following subkey: HKLM\System\CurrentControlSet\Services\MSExchangeIS\<ServerName>\Private-<MailboxStoreGUID>.
Change the value of Background Cleanup to 60000 (decimal) or to 0xEA60 (hexadecimal).
Close Registry Editor.
Restart the Microsoft Exchange Information Store service for the change to take effect.
Before you edit the registry, and for information about how to edit the registry, see Microsoft Knowledge Base article 256986, Windows registry information for advanced users.