I have my USB connected to my droid turbo and my laptop. I've looked at different solutions including the device debugging the usb option and no matter what I try, my computer says there is nothing connected to import. When I pull down the bar at the top of my phone, I don't have a bar that I can press that says USB charging and leads to more options. My phone has a little charging lightning bolt, but I don't have a clickable option to change anything in.
Not all USB cables are the same. Are you using the OEM charging and data cable that came with the phone? If not, there is really good reason to believe it is charge only, in which case NO computer is going to recognize the phone.
Second, try a different USB port. Many times the particular port forgets it can talk to a phone. First reboot the PC. Use the same port. Does it recognize the phone? If not, try another port... Now does it recognize the phone?
Third. Re-download the driver for your phone. Reboot computer try again.
Fourth, try a different computer. If it works, again, it's probably the cable.
$10 it's your cable.
If you've tried all the above and you want to try something different and you have WiFi, find an FTP server program for your phone. Go on the phone, on the web and search for SwiFTP_1.24.APK on the web from a reputable site. "Sideload it". OR find an FTP server program from the PlayStore. I like SwiFTP because it is lean and mean.
Now download Filezilla from the web onto your computer.
Start SwiFTP on the phone.
Start FileZilla on the PC.
Drag and drop files between the two over WiFi. Done.
There are other options like BlueTooth (if your computer has it). Google how to do it.