When using Matrox Cards in a Thunderbolt Expansion chassis, you need to disable Fast Startup under Windows 10.
To disable Fast Startup, first, open your power options by hitting Windows+X or right-clicking your Start menu and selecting Power Options. In the Power Options window, click "Choose what the power buttons do."
If this is the first time you've messed with these settings, you'll need click "Change settings that are currently unavailable" to make the Fast Startup option available for configuration.
Scroll to the bottom of the window and you should see "Turn on fast startup (recommended)", along with other shutdown settings. Just uncheck this box to disable Fast Startup. Save your changes and shut down your system.
