Windows 7 and win 2008 are searching for device-unresponsive solutions when adding devices

The discovery of the problem: a few days ago to do experiments, ready to add a piece of Microsoft Loopback Adapter virtual network card in Windows 7 network device, when entering "add Device", found to be stuck in "Searching for device ..." Make sure you can detect your device "for a long time there was no response. And my laptop and my desktop have the same problem. The system is genuine Windows7 Professional Edition, the system other applications are normal. Since Windows7 can not add a virtual NIC, then do the experiment on Server 2008, so Remote Desktop one of my servers, open "Add Device", found the same problem. As shown in the following illustration:

Windows Server 2008 R2 SP1

Windows 7 Professional Edition