We have a room that has been unused for a while. We noticed some faint spots appearing on the ceiling a couple years ago. The spots have slightly darkened over time but haven't changed in size or shape. I was not sure if it was mold or something else. We couldn't see any obvious signs of water damage or moisture in that area. We even looked in the attic. Other than these spots isolated in one corner, the ceiling and other walls look fine. We ignored it for all these years as the spots haven't really changed in size, shape or color but now we want to use the room and were planning on painting it when we noticed these spots again. Could this be mold? If so, is it dangerous or we can just put a good primer and paint it over?
They definitely look like water spots or leaks. You stated you've been in the attic and saw no sigh of leaks... have you been up there lately and actually looked at the drywall where the spots are? If no signs of any leaks, blotch some bleach over the spot. If it's an old water stain that might remove it. If you do paint, get a stain blocker and apply it per instructions before painting. It really does not look like mold. have you ever had any rodents up in the attic??
It's difficult to look at a picture to determine if dark spots on a ceiling are mold. Here are a couple links that may help you make the determination:
They look like water stains. Is this along the outside wall ? If so, probably caused by ice damming in the past if you are in an area susceptible to freezing. Now that you are monitoring them, watch out for further wetness. Don't worry though, once dry, prime and paint. Mold starts with dark spots on areas that stay moist.