I also can't get these to install.
Win7 x64 SP1. Brand new install, never even plugged in the HTC One (or any other phone) before. I plug it in, Windows says it found an Unknown device and couldn't install drivers (normal). I point it to these and when I try to set it, Windows says I'm already using the best driver. Like someone said earlier, it's probably a firmware issue and these drivers need to be updated. I did update to fw 7.15.401.1 recently so this might be why.
Google Nexus Devices ADB & Fastboot
Samsung Devices ADB & Fastboot
Asus Devices ADB, Fastboot & APX
HTC Devices ADB & Fastboot
[B]Windows 8 Instructions[/B]
How to Disable Driver Signature Enforcement in Windows 8:
From the Metro Start Screen, open Settings (move your mouse to the bottom-right-corner of the screen and wait for the pop-out bar to appear, then click the Gear icon).
Click ‘More PC Settings’.
Click ‘General’.
Scroll down, and click ‘Restart now’ under ‘Advanced startup’.
Wait a bit.
Click ‘Troubleshoot’.
Click ‘Advanced Options’
Click ‘Windows Startup Settings’
Click Restart.