While Scooby and the gang have solved hundreds of mysteries over the years, there are still a few that remain unsolved. The following list is of cases which we see in various episodes and films, but were never solved:
This is just a short list of observations related to unsolved mysteries that I made. I'm sure there are more, but I tried to just stick with things specifically relating to mysteries and not stuff like "we don't know how they got the Mystery Machine back" and "We don't know what happened when Dracula appeared at the window in the end of Reluctant Werewolf," because otherwise the list would take weeks/months to compile. If you can think of any I'm missing, I thought this could start a fun conversation in the comments.