I just updated to Photoshop 2018. I opened a file, did some work, went to save as> typed new name and hit ok. It starts to save then crashes. The first time I thought it was an annoying fluke so I tried again. Same thing. And again. Same thing.
I'm saving the file as a PSD file.
Running on Macbook Pro Retina Mid 2014 using OS X El Capitan Version 10.11.6.