Unable to unlock via Windows 8.1 Preview
I created this thread to hopefully prevent someone else from wasting countless hours doing the same as me in troubleshooting driver issues.....
If you are running Windows 8.1 preview and trying to get Windows to properly recognise your phone in fastboot and failing at every turn.... Just use another PC without Windows 8.1 Preview and it will work fine....
I wasted hours uninstalling and reinstalling various drivers etc only to fine Windows was the problem the whole time.
Took me 20mins to unlock the phone on my other PC with just Windows 8.
Sent from my HTC One using xda app-developers app