So one time, I accidentally opened a full folder of a ton of images, and it opened them all in Preview. If I select Quit, it asks me for every single image if I want to save it or not. This takes ages, and if I force quit the app it'll just ask again when I open it, so I went through all of them and said don't save. But, one Preview window with a bunch more pictures all at once in it still remains open with a dialog window saying "Saving" (akin to when you empty the trash) with a progress bar that never progresses. I've left it over night. How on earth do I just like "reset" Preview so I can use it again? I use that app regularly.