Hi Keith,
My name is Vic, from Matrox support.
For the Mac world, please confirm you have installed our 2.5 driver, and have your CS updates applied first.
In premiere, when you build a new project, when ‘The New Sequence’ window opens on the Sequence Presets pane, under Available Presets, select the preset that matches the type of sequence that you want to create from the Matrox Presets folder.
Now put some color bars on the timeline. Do you see them on our output monitor?
If not, and lets say for example you are using HDMI out, go to system preferences, launch the Matrox icon, and go to the video out tab, set the HDMI output dropdown to 1080i, instead of main channel.
Please keep us updated and let us know the type of cabling you are using, and if it is a direct connection.
Best regards
MVTS