P: Preparing slideshow hangs on slide # 2

This has been happening repeatedly in previous versions and hasn't been fixed in LR 6.5 (standalone). 
Steps
1.  Select some slides.  I'm using a filter to select slides that are 4 stars or higher.  There are 16 of them in the folder that match.
2. Go to slidshow and hit "play"
3.  The dialog box comes up "Preparing Slideshow" and below Preparing preview for slide #2.  It mostly hangs on # 2 but sometimes a different slide.  If I cancel and choose a different folder with no filters (all images) and hit "play" it hangs on # 2 again.
4.  BTW...if I hit the -> buttone (play) below the images, instead of the "Play" button in the right hand lower corner, it'll play.
5.  Also, based on some other input, I've tried turning off/on the GPU. No difference.