Nexus 7 + Windows 7 = "A device attached to the system is not functioning." when transferring files from Nexus to Windows I connected a Nexus 7 (rooted Android 4.4.2) to my laptop (Windows 7 SP1 x64 Ultimate). I see Nexus 7 in Windows Explorer and can browse the files in the Nexus 7, but when I tried to move files from Nexus to Windows I get the following error from Windows Explorer:



Reconnecting the Nexus 7 didn't help. Restarting Windows 7 did solve the issue, but I'm curious to know what can caused this error.
If you haven't already, try a different USB port and make sure your Nexus is unlocked. Afterwards get the newest Google USB drivers and manually replace the drivers through Device Manager.