After a recent Windows update, trying to connect my Google Nexus 5 phone did not work. Simply connecting the device brought a message that Windows did not recognize the device and the device was now recognized as an "Unknow Device".
After first trying a different USB cable, and then checking to update the driver the MTP/PTP settings was the culprit. After finding the thread at the link below, changing the setting from the Nexus 5 from MTP to PTP and then plugging the device back to my computer work. The computer finally recognized the Nexus 5 as a Portable Device!