Exchange Server: Quota cache / limits are only applied after a longer period of time

Some people are probably familiar with this problem: A user calls the helpdesk because their mailbox is full. Deleting it is of course not an option, because even the 10-year-old mails could be needed again. Discussion is usually pointless, so the limit for the mailbox is increased. Quite impatiently, the user now contacts the helpdesk every 15 minutes because Outlook still shows a full mailbox.

The background is as follows: The Exchange Server caches the limits for the mailboxes/databases and does not read in new limits permanently or immediately. In the default setting, this value is 2 hours. This applies to Exchange 2007, 2010 and 2013, so the user calls a few times within the 2 hours...

In order for the new limits to take effect immediately, you could restart the "Microsoft Exchange Information Store" service, but this will result in the databases being offline, at least if no DAG is present.

The user must therefore be patient. However, if you have such cases more frequently, you can adjust the interval of the cache (quota cache). To do this, two values must be changed or added in the registry:

The following DWORDs must be added under the key "[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem]":

• "Reread Logon Quotas Interval"
• "Mailbox Cache Age Limit"

The decimal value indicates the cache lifetime, i.e. 1200 seconds in the screenshot above, which corresponds to 20 minutes. In the default setting (even if the entry is missing), the value is 7200 seconds. The value recommended by Microsoft is 20 minutes. The "Microsoft Exchange Information Store" service must also be restarted for the changes to take effect. In environments with only one Exchange Server, this is probably not possible during day-to-day business. The user must therefore be patient...

In an environment with DAG, the settings must be made on each mailbox server, here the databases can also be swiveled accordingly in order to gradually change the registry value for all servers.