Go to the preferences of the Lightroom and under the performance tab
Un check the option which says"Use graphics Processor "
Restart the Lightroom and try again.
I did this and thought it was working, but my LR just crashed again after I hit the "r" key.
I've got the same on my Mac, El Cap, and 6.3. Everything up-to-date.
It seems like there is a problem while switching image while still previewing the other image. It crashes a lot at my system. With a lot, I mean more than 15 times within a few hours. It's not-workable like this. Please fix this.
I tested it with both GPU on and off. It was fine a few versions back, now it really messes everything up. I am kind of losing my patience here as a professional photographer. I am working with a non subscribed-cc version, whatever that is called exactly.
Again: please confirm that engineers are looking into this.