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Hosted Messaging and Collaboration (HMC) Support FAQ

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HMC Planning and Deployment


Which roles in HMC can I run on virtual servers?

  • None of the HMC servers are supported in a virtual server. HMC was only fully tested on physical servers. See
  • Hardware Virtualization Considerations
  • Microsoft currently does not support any version of Hosted Messaging and Collaboration solution using any hardware virtualization technology.

Is OCS 2007 R2 supported in HMC 4.5?

  • Yes, but only the functionality provided in OCS 2007 RTM is supported. None of the new R2 features or their provisioning are supported.

Is SQL Server 2008 supported in HMC?

  • No, only SQL Server 2005, for all HMC versions.

Is HMC supported on Windows Server 2008?

Is HMC supported on 64-bit operating systems?

Which HMC roles can I combine on a single server?

  • The only configuration that has been fully tested is the one described in the deployment documentation. However, hosters have successfully combined roles, even though this may reduce fault tolerance. One restriction is that you cannot install the MPS Web Services on an MPS engine server. You should also not install any HMC roles on a Domain Controller.

Is Forefront Online Protection for Exchange (formerly Exchange Hosted Services) supported with HMC?

  • Yes. Microsoft makes no recommendations as to which perimeter software should be added to HMC.

Is System Center Operations Manager 2007 R2 supported with HMC?

  • Microsoft has not tested Operations Manager 2007 R2 with HMC, but some customers are using it.

Which Operations Manager Management Packs should I install in an HMC environment?

  • You can install the latest Management Packs for each of the servers and their applications, as well as the Microsoft Provisioning System Management Pack, which is provided with HMC.


HMC Maintenance and Scalability


Is it supported to add the latest service pack of Windows/Exchange/SQL/OCS to my HMC environment?

  • Microsoft maintains test environments for HMC 4.0 and 4.5, and these are regularly updated as the service packs are released. Hosters should contact the Solution Support team to confirm that the latest service pack has been tested successfully.

Which hotfixes do I need to apply to my HMC platform?

  • Microsoft maintains test environments for HMC 4.0 and 4.5, and these are updated monthly with the latest security updates released to Windows Update. Hosters should contact the Solution Support team to confirm that the latest updates have been tested successfully, before deploying them. We recommend that all security updates are deployed. Hotfixes to server applications should only be deployed to fix a problem that has been observed on the platform, and only after careful testing in your test environment.

How many servers do I need to support my expected user load?

How many SMTP domains can I host?

  • Microsoft has tested HMC to over 2 million SMTP domains.

How many Offline Address Books (OABs) can I have in total?

  • There is a known issue with Public Folder OABs. Each of these generates a Replid and we have seen that more than approximately 20 000 of these can lead to an inability to create any further MAPI-enabled organizations. A workaround has been developed which allows small organizations to share an OAB; users are not aware it is shared. See  for details. A workaround is provided by the SharedOABUtility, which was provided in HMC 4.0 ( Note that this limit applies only to Public Folder-based OABs. Hosters expecting to have many thousand hosted organizations should deploy web-based OAB distribution in HMC 4.5.

How many Offline Address Books can I hold on a dedicated OAB server?

  • Microsoft recommends a maximum of 1000 Offline Address Books. It is possible to hold more than 1000, but hosters who choose to do so should monitor their Active Directory performance closely. For details, see
  • Hosters expecting to have many thousand hosted organizations should deploy web-based OAB distribution in HMC 4.5.


HMC Supportability


How do I obtain support for my HMC environment?

  • Proactive and reactive support from Microsoft Solution Support is available to customers who have a Solutions Support Addendum to their Premier or MSPA support contract. You can also obtain support from a Microsoft Hosting partner.

When does support for HMC end?


The Future


What is my upgrade path to Hosted Exchange 2010 and Hosted SharePoint 2010?

  • HMC 4.5 is the last version of HMC, and also of the Microsoft Provisioning System (MPS). It will not be possible to use MPS to provision the new hosted services provided in Wave 14 products (Exchange 20210, SharePoint 2010). SharePoint Foundation 2010 and SharePoint Server 2010 are natively multitenant. Exchange 2010 will be multitenant capable when Exchange 2010 SP1 is released. Exchange 2010 RTM is not supported in a multitenant configuration.
  • There are several routes to realizing the benefits of the services in Exchange 2010 and SharePoint 2010:
    • Become a reseller or syndicator of BPOS
    • Engage a Microsoft hosting partner to assist in deploying a complete hosting solution
    • Become a reseller of services provided by a private-label hosting provider
    • Develop a complete solution by adding a control panel and provisioning services to the base products

I am running HMC 4.5 including OCS 2007, what is my upgrade path?

  • Microsoft has published guidance on building and migrating to messaging and collaboration cloud using Exchange Server 2010, SharePoint Server 2010, OCS Server R2