I've had many occurrence of Photoshop CS 6 crashing when using the spot healing brush along the bottom edge of an image. Brush size is usually in the 10 to 20 px range, hardness in the 80 to 100% range, Mode is Normal, Type is Content-Aware. Most recent crash was on a tif image of about 30 Mb. I'm "cleaning up" images that have been scanned from 35 mm slides. My general work flow is to start at the top and work down removing dust specks and other imperfections in the image. I usually have to do a little bit of cleanup along the image edges where the slide mount is not always free of fibers or the slide was not quite aligned properly in the scanner. I've not had problems working on the top or side edges. Once this clean up is completed I may make other adjustments to color and exposure. I usually try to remember to save the image before I do clean up along the bottom edge. When I do remember I don't think I've had a crash. When I forget I've definitely had crashes.