When I am grading assignments that have been submitted as PDF files about 3 out of 15 won't open on my computer. The other 12 are fine and open nicely, but those 2-3 say that the file is converting and may take up to 10 minutes.
The weirder part is that they open fine on my iPad. As a work around I'm grading with both devices side by side, but ideally all the files would open on my computer.
Any suggestions on what is happening?