IMPORTANT Notice: the Update for Windows Server 2003 (KB968930) causes the Exchange 2007, Exchange 2007 Mobility and Exchange 2007 Unified Messaging providers to fail with an error similar to the below:

    <response>

    <errorContext description="A parameter cannot be found that matches parameter name 'Alias '.

    Cmdlet='Enable-Mailbox'
    DomainController='AD01.Fabrikam.Com'
    Identity='LDAP://CN=User02@ConsolidatedMessenger.com,OU=ConsolidatedMessenger,OU=Hosting,DC=fabrikam,DC=com'
    Database='P1FTEXM1\BusinessMailstore1'
    Alias='User02'"

    code="0x80131600" executeSeqNo="268">

    <errorSource namespace="Exchange 2007 Provider" procedure="CreateMailbox"/>
    <errorSource namespace="Managed Email 2007" procedure="CreateMailbox"/>
    <errorSource namespace="Hosted Email 2007" procedure="CreateBusinessMailbox_"/>
    <errorSource namespace="Hosted Email 2007" procedure="CreateMailbox"/>

    </errorContext>

</response>

Uninstalling the Update will fix the issue most of the time. If it does not you will have to remove and redeploy Windows Powershell 1.0 and the Exchange 2007 Management Tools Role including the matching Exchange Rollup to the affected servers after removing the fix.