Disorganized implies that something was organized at some earlier time, but is no longer organized now. Unorganized does not imply one way or the other whether something was organized in the past. It may always have been unorganized. I myself am not organized now, and have never been organized (though I've come close). Therefore, you can call me unorganized. Many people would not notice the difference, however.

Thank you :)))))

Good question!