"Cleaning up temporary files"

I don't know if this helps but I recently ran into this problem. Was very concerned to see this issue has existed since 2016. When it first occurred earlier this week I rebuilt (copy pasted) into new powerpoint as a work-around. I was able to publish several times. Then it happened again (same course). So this evening I used the Check for Issues Inspector. It indicated something about personal information and removed it. After running the inspector it also reset my player and publishing settings. So I reloaded my player  and  added my publishing settings and that seemed to fix it. Much better than rebuilding the course.