Learning froze and no buttom to resume training- Any suggestions on how to fix?

Summary:

a users learning froze about 60% of the way through. When he went back in to complete it, there was no resume button.

Content (required):

We were ultimately able to fix this issue (I deleted him out of the course and then re-enrolled him), but a users training froze about 60% of the way through. When he went back in to complete it, there was no resume button. HRSolutions withdrew him and he went back in and tried again, but no resume button or launch button appeared. I went in today and deleted him out and then re-enrolled him in the offering and he was able to get through with a resume button.