That looks a lot like a video driver/GPU issue.
Please let Apple know about this, so they can get the information they need to fix the bugs introduced in MacOS 10.10.
I'll do that and search their discussions too. Is there a better way to describe this, or some keywords I should look for?
I'll search video driver/GPU of course, so thanks for that ;-)
Something to try in Photoshop, temporarily -- turn off GPU drawing in Photoshop's preferences (Prefs -> Performance, bottom right corner), then relaunch Photoshop.
If that helps, then the cause is definitely in the GPU driver (and we can try additional diagnostic steps to isolate the problem).
OMG, thanks, at least I can get some work done. I've processed about 10 images with no problems.
I'm happy to try other things if you don't mind trying to narrow it down.
Thanks again ;-)
OK, so we know it is the GPU, but we don't know what part of the GPU code.
Try turning the GPU back on, go into the the advanced GPU prefs and set the mode to "Basic", then relaunch Photoshop and see what happens.
Changing the mode to "Basic" disables the shaders that do color management, while still using OpenGL for image display. If the problem is in the driver shader support, then you may still be able to use most of the GPU features until Apple can release a patch. If it is still messed up on "Basic", then we know that even simple OpenGL image display is hosed, and you'll have to keep the GPU turned off until Apple can release a patch.