By default, the computer will not recognize the Nexus 5 when you plug it in. The Nexus 5 will not connect to a computer in MTP (Media Transfer Protocol) mode or as an external hard drive unless the option is enabled. The user will need to enable MTP setting for the computer to recognize the phone and allow access to the files inside the phone including the pictures, videos, and music.
How to Enable MTP Mode on the Nexus 5
1. On the home screen, slide down from the top to access the notifications menu. Press on the face icon on the top right of the screen
2. Press ‘Settings’
3. Press ‘Storage’
5. Press ‘USB computer connection’
6. Enable ‘Media device (MTP)’
7. Connect the device via micro USB and you should now have access to the phone’s internal drive