Name: Sierra Wireless MC8775 HSDPA Modem Driver
Author: Sierra Wireless

Question 1

Install fails or rolls back?

Accepted Answer

Run the Sierra Wireless installer as Administrator and, on newer Windows, use compatibility mode for XP/Vista/7 or temporarily disable driver signature enforcement. Match the package to the OS architecture and the MC8775’s carrier firmware.

Question 2

Device not detected?

Accepted Answer

Enable the WWAN/mini-PCIe slot in BIOS, check the laptop’s wireless/WWAN switch, reseat the MC8775 card, and verify the SIM is inserted. A BIOS whitelist can also block unrecognized WWAN cards.

Question 3

Version conflicts/COM port errors?

Accepted Answer

Uninstall old Sierra Wireless drivers and Connection Manager, delete leftover modem/COM-port entries in Device Manager, reboot, then install one matching driver package. Avoid mixing generic Sierra drivers with OEM MC8775 builds.