Ive already found the problem but can anyone shed some light on how this happened? This morning I just happened to check and I had 41gb free on my hdd. Ive not added anything to it today. I went to make a short, 5 second movie in imovie. I had a sound bit I was going to add to a video clip. So I pieced them together and saved the project. I was tinkering around and was going to trim a little off the original video clip in quicktime but it said "cannot save, start up disk almost full." So I checked and only had 8gb left. Then my mini just totally froze up, couldnt do anything. I assume something was being written to the hdd is why. I tried to log out and back in, but after about 5min being stuck at the log in screen, I just powered it down. When I start back up I check the hdd and it showed 10gb free, which still left a mysterious 30gb missing from this morning. I moved everything associated with the video clip I was making to the trash, thinking that was the only thing it could be, even though the files I was using were tiny. Before I emptied the trash I ran omnidisksweep, and there in the trash, was a 32gb movie file, the one I was working on. How did a 4 second movie turn into a 32gb file? The video clip is 364kb and the audio clip I was going to use is 32kb. Weird.