Currently trying to unlock my bootloader, but cannot get my nexus 6p to determine that it's connected to my PC. I can use adb commands while it's on, but booting it into fastboot mode with the adb command or with the key combination results in 'connect usb data cable'. I have rebooted my phone, my computer, reinstalled ADB, installed the google drivers both manually as well as with the SDK manager and used 4 different cables.
I have also tried all 2 of my usb 2.0 ports as well as all 6 usb 3.0 ports.
Windows plays the sound confirming that a device has been connected.
I am using windows 10.
Here's a screenshot of the device manager: