When I download a video, it results in a file that says The document "your file" could not be opened. The file isn't compatible with QuickTime Player. Why does parallels do this? Why isn't it making a quicktime compatible file? Is there a way to MAKE it do what it's supposed to? (that is download a video that works in quicktime) It used to work flawlessly every time, now it hardly works at all. It always makes an unopenable file....
If this is for Parallels Toolbox for macOS, then you might get better support in the appropriate channel: https://forum.parallels.com/forums/parallels-toolbox-for-mac.762/