File unexpected stopped working

I have done my own troubleshooting with the update that came out today .  For me, it's when I try to use animation and have the sequence chosen to come in by paragraph....nothing will show when previewing the slide.  I change back to either no animation, or sequence to be one object, and all works fine in preview.  This is an issue since this course has haver 300 slides, with many already being completed using sequencing by paragraph.