The MailboxCountQuota policy is not enforced correctly in an Exchange Server 2010 hosting mode

Applies to: Exchange Server 2010 EnterpriseExchange Server 2010 Standard


Consider the follow scenario:
  • You install Microsoft Exchange Server 2010 in hosting mode by using the /hosting switch.
  • You create a tenant organization in this environment.
  • You run the Set-RecipientEnforcementProvisioningPolicy cmdlet to specify the maximum number of mailboxes that can be created in the tenant organization.
  • You create two additional mailboxes within 5 minutes when only one mailbox can be created based on the specified maximum number.
In this scenario, both mailboxes are created successfully.

Note The expected result is that the second mailbox, which exceeds the maximum limit, should fail with the following error message:

The following error occurred during validation in agent 'Provisioning Policy Agent': 'The number of "Mailbox" objects in the organization "Organization Name" has reached or exceeded the resource quota (the number of quota) enforced by policy "Organization Name\Recipient QuotaPolicy".'


This issue occurs because the mailbox count is read asynchronously, and the mailbox count in the cache is not updated when the mailbox which exceeds the limit is created.


To resolve this issue, install the following update rollup:
2645995 Description of Update Rollup 1 for Exchange Server 2010 Service Pack 2


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about the Set-RecipientEnforcementProvisioningPolicy cmdlet, visit the following Microsoft website:
For more information about hosting mode, visit the following Microsoft website:
For more information about how to manage Tenant Organizations cmdlet, visit the following Microsoft website: