#Hyper-V 2012 R2 - Virtual Machine unknowns device (Windows 2008 R2 / 7 and below)

If you install Windows 2008R2/2008/7/Vista as virtual machine in Hyper-V 2012 R2, and notice unknown devices show in device manager.

Actually one is Automatic Virtual Machine Activation (AVMA), and another one is Remote Desktop Control Channel/Enhance Session Mode. This two features are new in Windows Server 2012 R2, and required virtual hardware. 

Solution:

1. You can find the driver in Hyper-V 2012 R2 integration service setup disc or download the driver from link below:

    32 bit driver

    64 bit driver

2. Update the driver manually in device manager.

3. Restart Computer.