For the past 2 days I've been having major issues with PS CC 2017.
Just now I copied & pasted a portion of one file into another (both files are the same size & resolution, one being a modified duplicate of the other) and the pasted portion resized itself to huge. I was able to resize it but it's just weird and annoying.
Yesterday the photocopy filter just stopped working ... instead of doing what it does it just came up with a grey screen regardless of what setting I used. I tried clearing the cache, rebooting, and finally reinstalling it completely. Didn't help at all.
Earlier yesterday I had drawn a path around an object to delete the background. The whole image ended up with a dark 1-2 pt line through it. Tried a bunch of stuff and nothing fixed it. Finally had to fix it with the clone tool.
Running on a MacBook Pro (Retina, Early 2013), OS X El Capitan v 10.11.6
Is it a really buggy version or what?
Did you Try to reset the Preferences ?
Edit -> preferences -> General Click on Reset Preferences on Quit then Restart Photoshop.