Not sure what you mean by “ml file as a shortcut”.
Did you also put all of your source media files on that same hard drive? If not, just saving the MLT project file will not open your project.
If you are missing your media files, you would have got a Missing Files dialog box asking you to point to those file locations so Shotcut can fix the MLT.
Here is a project file I created with 21.02.29, the same version you have installed.
countdown.mlt (6.6 KB)
This doesn’t need any media sources, as everything in the project is all created with Shotcut directly.
