<p>What do you know about a “DR” grade. No letter or explanation from the prof. No known problems.</p>
<p>Here’s what’s on their website:</p>
<p>Deferred Report Grades
Students may receive a Deferred Report (DR) grade when the instructor believes their work to be complete but cannot assign a grade because of disciplinary proceedings or other problems. If students are given a DR grade, the Office of the Dean of Students assists them in resolving the problem. For graduate students, the dean of the Graduate Division sets a deadline by which the DR lapses to an F if the problem is not resolved and a grade assigned. The DR is changed to a grade, or perhaps to an Incomplete, when the instructor provides written confirmation that the situation is resolved. The DR grade is not included in determining the grade-point average.</p>
<p>Sounds like you need to contact the Office of the Dean of Students.</p>