I have a VirtualBox process hanging around which I tried to kill (KILL/ABORT) but without success. The parent pid is 1 (init).
top
new here and not that experienced, but I had the same issue where I could see my processes going into uninterruptible sleep (D state) when I checked their status using htop. For some reason,
kill -9
worked for me. Maybe you can try the same.
Edit: the detailed answer is up there by ostrokach (which I didn't see).