During my first steps in Shortcut I encountered the first problem. As you see in the screenshot below, I cannot see anything of the video in the preview window. Instead there is a green screen. It doesn’t matter whether I import a JPEG file or a MOV file or a mp4 file … I can’t see nothing of it in the preview. But when I export it and open the file in the Media Player it works so the the source data cannot really cause the problem.
What machine (PC, Mac, Linux)? What OS and OS version? What hardware (GPU, memory, CPU)? What version of Shotcut (16.11.02 is the current rev,)? Are you seeing this when the file is on the timeline or source display? How are you importing the files?