Symptoms
In an Exchange Server 2013 environment, ActiveSync devices cannot be removed from a mailbox when there's a forward slash in the DeviceType property. This issue occurs when you use the Remove-MobileDevice or Remove-ActiveSyncDevice commands, or when you remove the device by using the Exchange Control Panel (ECP).When you try to remove the device, you may not receive an error message, and the Get-MobileDevice cmdlet may no longer show the device. However, the Get-MobileDeviceStatistics cmdlet will show it.
Cause
This issue occurs because the forward slash is parsed incorrectly.
Resolution
To fix this issue, install Cumulative Update 12 for Exchange Server 2013 or a later cumulative update for Exchange Server 2013.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology that Microsoft uses to describe software updates.
