There exist a case in the Windows 7 USB disk driver where an unresponsive USB controller for a hard disk drive will hang the process calling the driver, for example explorer.exe, and make it impossible to terminate the process. If this occurs when copying a file to the disk through explorer.exe the Copying dialog will not close when Cancel is pressed, and the dialog's explorer.exe process will be locked by the kernel so that it can't be terminated. If this occurs when shutting down Windows the shutdown will halt indefinitely. Disconnecting the drive will immediately free the process so that its GUI loop continue and it can be terminated. I ask the Microsoft drivers team to register a bug ticket for this behavior and change the behavior to be more similar to the behavior when for example a network drive becomes unavailable. I.e. not lock the calling process by the kernel indefinitely. Thanks!

Hi, This type issue occurs may be caused by the damaged components. To fix this issue, please try to reinstall the USB controller. First, please disconnect all USB devices and then perform the following steps: 1. Click "Start" button, type devmgmt.msc (without quotation marks) in the Search bar and press "Enter". Click Continue if necessary. 2. In Device Manager, double click to expand "Universal Serial Bus controllers", right click on the Host Controller, click "Uninstall" and click "OK". 3. Repeat the step 2 to uninstall all items under "Universal Serial Bus controllers". Then, restart your computer and Windows 7 will reinstall all USB controllers automatically. Meanwhile, the third party programs may lead to this issue also. As a result, please test it in Clean Boot environment.Kim Zhou TechNet Community Support