Question 1

Install fails or rolls back?

Accepted Answer

Run the U600 driver setup as administrator and use the latest signed package. If Windows blocks it, temporarily disable driver signature enforcement, install, then re-enable it.

Question 2

Modem not detected?

Accepted Answer

Try another USB port/cable, confirm the U600 is not in storage-only mode, and check Device Manager for an unknown device. Update the driver manually by pointing to the extracted INF file.

Question 3

Version conflicts?

Accepted Answer

Uninstall older U600/EVDO modem drivers and modem-manager software, reboot, then install only one driver version. Remove duplicate COM-port entries in Device Manager if they persist.

U600 EVDO Modem Driver