The Desktop Experience feature is not enabled on a Windows Server 2008 server, or on a Windows Server 2008 R2 server.
You install the Microsoft Unified Communications Managed API (UCMA) Runtime on this server.
You successfully install the Microsoft Exchange Server 2010 Unified Messaging server role on this server.
In this scenario, the Microsoft Exchange Unified Messaging service cannot start. Additionally, the following event is logged in the Application log:
Log Name: Application Source: MSExchange Unified Messaging Event ID: 1001 Task Category: UMWorkerProcess Level: Error Keywords: Classic Description: The UM worker process (UMWorkerProcess.exe) couldn't start. More information: A file couldn't be converted for playback over the telephone: An error occurred in the Audio Compression Manager: The operation completed successfully.
Note By default, the Microsoft Exchange Unified Messaging service is started after you install the Exchange Server 2010 Unified Messaging server role on a computer.
This issue occurs because the Desktop Experience feature is required for the Exchange Server 2010 Unified Messaging server role installation. However, the prerequisites verification incorrectly passes in the scenario that is described in the "Symptoms" section.
To resolve this issue, install the following update rollup:
2579150 Description of Update Rollup 4 for Exchange Server 2010 Service Pack 1
To work around the issue, install the latest version of UCMA Runtime, enable the Desktop Experience feature, and then restart the Microsoft Exchange Unified Messaging service on the server.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the Desktop Experience feature, visit the following Microsoft website: