After you upgrade to Microsoft Exchange Server 2010 Service Pack 1 (SP1), some users no longer receive quota warning messages even though their mailbox size is over the quota warning threshold.
The way that quota warning messages are generated changed in Microsoft Exchange Server 2010 SP1. Before SP1, all mailboxes on a server are checked during the quota warning schedule to see whether the mailbox size exceeds the quota warning threshold. If the mailbox size exceeds the threshold, a quota warning message is created for that mailbox.
In SP1, a new flag was introduced that controls if a mailbox is checked to see whether its size exceeds the set warning threshold. This flag is set on a mailbox if the mailbox size is equal to or more than 50 percent of the Prohibit Send quota.
Therefore, if the warning quota is set to a value that is less than 50 percent of the Prohibit Send quota, the mailbox size can be over the warning quota limit but still not over 50 percent of the Prohibit Send quota. In this case, the mailbox is not checked to see whether it has exceeded its threshold, and the mailbox does not receive a quota warning message.
Consider the following scenario. You have a size limit of 10 megabytes (MB) that is set on your mailbox, and you set your Prohibit Send quota to 8 MB. Therefore, the user can no longer send any email messages after he or she hits that 8 MB limit. However, the user can continue to receive mail up to the 10 MB limit. In this scenario, if you set your Warning Quota to 3 MB (notice that 3 MB is less than 50 percent of your Prohibit Send quota), the warning is not sent.
In addition, after a mailbox has been checked during the database QuotaNotificationSchedule, the flag is cleared. This means the mailbox is not checked again until the flag is reset. The flag is reset when either a message is saved in the mailbox or a message is sent to or from the mailbox. At that point, if the mailbox size is more than 50 percent of the Prohibit Send quota, the flag is reset, and the mailbox is checked during the next time slice of the QuotaNotificationSchedule.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To resolve this issue, follow these steps:
Install the following update rollup package:
2608646 Description of Update Rollup 6 for Exchange Server 2010 Service Pack 1
After you install the update rollup package that is described in step 1, modify the registry. To do this, follow these steps:
Click Start, click Run, type regedit, and then click OK.
Locate and then click the following registry subkey:
On the Edit menu, point to New, and then click DWORD Value.
Type CheckWarningQuota, and then press Enter.
Right-click CheckWarningQuota, and then click Modify.
In the Value data box, type 1, and then click OK.
Exit Registry Editor.
Restart the Microsoft Exchange Information Store service.
If an administrator has to see whether mailboxes are over Warning, Prohibit Send, and Prohibit Send and Receive storage limits, the administrator can increase diagnostic logging by following these steps:
Open the Exchange Management Console.
Expand Microsoft Exchange On-Premises.
Click Server Configuration.
Select the server name under Server Configuration for which you want to increase logging.
Click Manage Diagnostic Logging Properties under the Actions pane.
Expand 900 Private.
Click Storage Limits.
Click Expert, and then click Configure.
You do not have to restart the MSExchangeIS service or unmount and remount the database stores for this setting to take effect.
The next time that QuotaNotificationSchedule runs, events that list mailboxes that exceed the following limits are logged in the Application log:
Issue Warning Storage Limit
Prohibit Send Storage Limit
Prohibit Send and Receive Storage Limit
Note To see the QuotaNotificationSchedule for each database, run the following command: