If you have installed the driver but the machine isn't responding, check the following:

Unplug the USB cable connecting the M Mark M300 to your computer. Keep the printer turned off during the initial software setup to prevent Windows from installing a generic, non-functional driver. Step 2: Run the Installer

This guide is designed to help you cut through the confusion. It will act as a detailed troubleshooting flowchart, helping you identify your specific device by its unique characteristics. For each of the most likely devices, we’ve compiled the best sources and step-by-step instructions to download and install the correct, safe drivers.

After all drivers are installed, restart the M300. Then test: