Kirk: thanks for the reply. Yes, I do apply sharpening in camera so that I can check sharpness in the LCD and I don't think I'm the only person who applies in camera sharpening. However, as soon as I edit a photo in NX2, my first step is to undo in-camera sharpening. I'll do editing and apply sharpening as needed for output. What you have mentioned doesn't explain why sometimes the edited image appears pixelated and other times the same image doesn't appear pixelated. So what you saw are images (not pixelated/pixelated) that have been sharpened in Post. It also doesn't explain why when the pixelated image appears, the only way to quit PM is via Force Quit. Your answer ignores earlier provided info. No need to pursue and not the end of the world as I'll just force quit from time to time. Richard