Name: MosChip PCI Serial Port Driver
Author: MosChip

Question 1

Install fails or rolls back?

Accepted Answer

Run the MosChip installer as administrator, disconnect other serial adapters, and reboot before retrying. If it still fails, update the driver manually in Device Manager via “Update driver” > “Browse” to the downloaded INF folder.

Question 2

Device not detected?

Accepted Answer

Check Device Manager for an unknown “PCI Serial Port” or yellow warning. Reseat the PCI card, try another slot, and confirm the port is enabled in BIOS/UEFI. Install the driver before connecting serial peripherals.

Question 3

Version conflicts or wrong COM port?

Accepted Answer

Remove any older MosChip/Prolific serial drivers, reboot, then install the current package. In Device Manager > Ports, open the MosChip port’s Properties > Port Settings > Advanced to assign a free COM number.