Question 1

Installer fails or rolls back?

Accepted Answer

Run the ZTE AC2791 driver package as Administrator and use the Windows version it supports. If Windows blocks an unsigned/older driver, temporarily disable driver signature enforcement, then reinstall and reboot.

Question 2

Device not detected?

Accepted Answer

Try a rear USB port directly on the PC, not a hub. In Device Manager, check for “Unknown device” or a ZTE CD-ROM/modem entry; uninstall it, replug the AC2791, and let the correct modem driver install.

Question 3

Version conflicts or unstable connection?

Accepted Answer

Remove existing ZTE/Qualcomm modem drivers and old AC2791 entries in Device Manager, reboot, then install the latest package. Prevent Windows Update from replacing the driver automatically.

ZTE AC2791 Driver