by Blair Goodlin.
Thanks for all the input. It isn't a unoconv issue; we did have it installed incorrectly, but it was fixed. I discovered that Moodle will attempt to create the PDF once, and if it succeeds then it won't rebuild it again. The problem is that the instructor checked the assignment before unoconv was fixed, creating the blank PDF. Now, every time we try to preview the assignment in the grading interface, we're seeing that blank PDF even though unoconv is now installed correctly. At least new submissions will appear as they should.
