Hello, My Macbook (late 2008, running Mavericks) has suddenly started experiencing problems due to memory usage. I have about 7 GB of free space on my HD, which is not a lot, but typically not a problem. The problem that I've just been experiencing is that the available space goes down to less than 1 GB. When I check Activity Monitor, I see that the memory usage is atypically high. The "swap used" had suddenly shot up to 4-7 GB (and this is what caused the sudden decrease in HD space). The combination of the lack of HD space with the writing to the HD instead of RAM means that my computer becomes very slow. My Macbook, which has 6GB of RAM, typically has zero "swap used". I am running the same programs I always run: Firefox, Word, Preview, iTunes. I have noticed that quitting Firefox, which is the biggest memory user at 0.5-1.5 GB, sometimes solves the problem, but not every time. Any suggestions? What could have caused this spike when I'm using my computer the same way I always do. Thank you.