Unfortunately CrazyTalk 8 was released at a time when ultra HD monitors weren't popular so it doesn't support 4K or other Ultra HD screens. The optimized resolution for CrazyTalk 8 is 1920 x 1080.
If CT8 is currently unusable at your current resolution, then you can change the screen resolution on your computer.
To do this right click the Desktop and select "Display Settings". Then adjust the resolution dropdown to the required setting.
Peter
Forum Administrator
www.reallusion.com