Try this - go to the Cubase Preferences (Under the file menu in version 9.0.40). Under Editing --> Audio --> On Import Audio Files, select 'Use Settings', and check the boxes below, or at least the first box. This should bypass the dialog box that asks you what you want to do when you are dragging a track, and perhaps the crash specifically happens in this dialog box. Incidentally, you might also want to install the Cubase 9.0.40 patch. Try dragging one track at a time and see if it works.

Andrew
PG Music Inc.