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Mailbox Cache Age Limit has been set

[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]  

Topic Last Modified: 2007-01-15

The Microsoft® Exchange Server Analyzer Tool checks the registry of the Exchange Server computer for the presence of the Mailbox Cache Age Limit registry entry. This registry value is present at:


If the Exchange Server Analyzer finds the Mailbox Cache Age Limit registry entry present and configured with a value of 1 or greater, a non-default configuration message is displayed.

Exchange Server allows size limits (quotas) to be set on mailboxes. Quota settings are stored in the Active Directory® directory service and Exchange Server periodically reads the information in Active Directory to determine whether any changes were made to these limits. By default, Exchange Server caches this information for a period of two hours (120 minutes), after which it re-reads the information in Active Directory.

The Mailbox Cache Age Limit registry value, which is represented in minutes, is used to override the default time period. It is especially useful in a situation where a user cannot access their mailbox because the mailbox limit has been reached. If the default cache age limit is in effect, the user will not be able to access their mailbox for up to two hours. The recommended value is 20 minutes. Do not set this value too low because this can cause performance issues.


This article contains information about editing the registry. Before you edit the registry, make sure 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 Regedit.exe or Regedt32.exe.

To revert to the default configuration

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\System\CurrentControlSet\Services\MSExchangeIS\ParametersPrivate

  3. In the right pane, locate and delete the Mailbox Cache Age Limit value.

  4. Exit the registry editor and 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 the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (

For more information about the Mailbox Cache Age Limit registry value, see the Knowledge Base article 327378, "XADM: Exchange 2000 and Exchange Server 2003 Mailbox Size Limits Are Not Enforced in a Reasonable Period of Time; Fix Requires Exchange 2000 SP3" (