Name: HTC ThunderBolt ADR6400L Driver
Author: HTC

Question 1

Device not detected in Windows?

Accepted Answer

On the ThunderBolt, enable USB debugging under Settings > Applications > Development and select the correct USB connection mode. Use a known-good data cable and try a rear USB 2.0 port. If Device Manager shows an unknown device, update the driver manually.

Question 2

Driver installation fails?

Accepted Answer

Windows may reject the older HTC ADB/USB driver as unsigned. Run the installer as administrator; if needed, temporarily disable driver signature enforcement, then reinstall and reboot.

Question 3

Version conflicts with HTC Sync?

Accepted Answer

Existing HTC Sync or older ADB drivers can override the ADR6400L driver. Uninstall HTC Sync and prior HTC/ADB drivers, reboot, then install only the ThunderBolt driver package.