I updated my Nexus 7 to Android 6.0.1. Then I plugged it into my Win 7 computer via USB as I've done many times before. In Windows Exploring, I can see the Nexus 7 but can't see any contents, nor can I copy a file to it. When I try to copy a file to it, I get "Cannot copy item - The device has either stopped responding or has been disconnected."