The canvas does not show the media and displays black, shows artifacts, or displays the desktop instead of the media on the timeline.
- Click Edit > Preferences > Advanced in Camtasia.
- Change the dropdown to Software Only Mode under the Hardware Acceleration section and then click OK.
- Close and re-open Camtasia and see if that works.
If that still does not work, re-encode your video to an MP4 file that we can work with properly with your computer:
Download link for Handbrake
Video on what settings to choose in Handbrake: