Nexus 5 (Marshamallow) constantly mounts & unmounts with USB connection to PC

[AC Question]

I updated my Nexus 5 to Android 6 Marshmallow last night. Today I connected it to my Win7 desktop to charge it (as I've always done), and the Windows computer constantly mounts & unmounts the phone as an external drive (every second or two). I have never connected the phone to this computer as an external drive nor have I changed my phone or desktop settings.

The phone did not prompt me with with any choice about the USB connection.

 

[B. Diddy]

Welcome to Android Central! Try a different cable or a different USB port. Also try connecting other phones to that computer--does the same thing happen?