I'm still having issues trying to get ADB to work for me. I previously had an HTC Droid DNA which I had ADB working on this computer, so I suspect there's something lingering screwing me up. I've gone through and removed any trace I could find of HTC drivers, HTC applications, ADB, etc.
I installed the latest HTC drivers, and uninstalled the Sync Manager. I verified my ADB version is 1.0.31. I have enabled developer options and unknown sources. When I plug my phone in, it says 'USB debugging connected" but I have NEVER been able to get it to prompt me to authorize my computer or anything like that. 'adb devices' shows nothing every time. I'm still running 4.4.2 everything stock (no OTAs) and have S-OFF via Sunshine.