I've seen many threads about QuickLook acting funny, but none of the problems I've read were identical to mine. In my case, I don't think it's only QuickLook that malfunctions, it's the general image thumbnail display functionality altogether. Mac OS X version 10.7.5 As far as I know, there are 2 "fast" image preview functions on Mac (note that I am NOT talking about opening a file in the "Preview" application). (1) When I'm in a folder on my desktop, I'm always using the "columns" view mode (3rd of the 4 viewing buttons). When I click once on an image, the right-most column usually displays a thumbnail of the image. This is NOT, as far as I know, the QuickLook function. I refer to this as "image thumbnail display." (2) When I'm scrolling through images, as stated above, the "image thumbnail display" gives me an idea of what I'm looking at. But when I want to see a larger version of the image, I hit spacebar, and a larger version now shows up. This is QuickLook. And the beauty is that I can use my keyboard arrows to scroll through the images very quickly. So here's the problem. I scroll through hundreds of images all the time (eps, psd, jpeg, tiff, pct, etc.). I know for sure that both, "image thumbnail display" and QuickLook are fully capable of previewing these images. But as I'm scrolling through them, the images suddenly stop showing up. This happens in both, "image thumbnail display" and QuickLook. When one stops, the other stops. Instead of seeing contents of the image (i.e., the drawings), both functions will simply display file-information (such as file type, file size, file icon image, etc.) I used to think that I simply clicked on a bad file, but when I start scrolling backwards towards files that I just looked at two seconds ago, even these won't display properly anymore. So far, the only solution has been to log out and log back in. This fixes it every time, but the problem will happen again within minutes, if not sooner. It's getting to be a humungous waste of my time to log out and log back in. I've noticed that the malfunctions are triggered by the following: (1) Simply scrolling through too many images. If I'm in a folder with a ton of images, and I'm scrolling through them with my arrow keys, at some point, the malfunction will occur. (2) Changing the name of a file within that folder. Simply changing the file name of one of the files within the folder will cause the malfunction. Sometimes, I think, changing the file name of any file will cause the malfunction (such as a file not located in the folder of all the images). (3) Adding something to that folder. When I drop in a new image, the malfunction will occur. I'd like to fix this problem permanently so that it doesn't happen anymore. Alternatively, if there is no permanent solution, I'd like to find a temporary fix that is faster than logging out then back in again. Please help. Thanks!!