We've discussed this before. Just making sure: Do you DELETE an unwanted Project File from the Windows Explorer window (or) from navigation, (whilst having MEP open)?
I don't think it matters as long as the program allows you to. Sometimes some files can't be deleted in the program because the program tells you they are in use. In which case be careful but personally I have, and do both.
Accidentally deleted a file using the delete icon located above the timeline. It never asked if I wanted to delete from the library or PC. I wonder where I can retrieve it from. So far I haven't found them in my files. And why can't I stop the automatically download files when I start a project. Also are they removed from the files or just copy?
The delete button above the timeline, as shown below, or the keyboard Delete key on your keyboard, only remove the selected object(s) from the timeline.
They do not delete the actual files in the folder where they are located.
However: if you used the Delete key, on your keyboard, with an image or video selected in the Media pane, then the selected image/video will be deleted and end up in the Windows Recycle bin.
The timeline Delete icon is not activated when media in the Media pane is selected