You have a mailbox in an environment that has Update Rollup 2 for Microsoft Exchange Server 2010 Service Pack 2 (SP2) or a later update rollup that was released before Update Rollup 6 for Exchange Server 2010 SP2 installed.
You use a Windows Phone-based or Windows Mobile-based device to access the mailbox.
You synchronize the device with the mailbox.
An administrator runs the Get-ActiveSyncDeviceStatistics cmdlet to retrieve statistics for the device.
In this scenario, the User-Agent field in the results is empty. The expected behavior is that the field contains device information, such as the operating system that is running on the device and the version of the operating system.
This issue occurs because the Windows Phone-based or Windows Mobile-based device does not provide the value for the User-Agent field. Therefore, Exchange ActiveSync incorrectly updates the field.
To resolve this issue, install the following update rollup:
2746164 Description of Update Rollup 6 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.
For more information about a similar issue, click the following article number to view the article in the Microsoft Knowledge Base:
2678361 The user-agent information about an Exchange ActiveSync device is not updated in an Exchange Server 2010 environment
For more information about the Get-ActiveSyncDeviceStatistics cmdlet, go to the following Microsoft website: