Experiencing a Decrease in Hard Drive Space

A quick search of this forum revealed this question hasn't been asked in a number of years, and it didn't really receive a solution. I have a 2.33 GHz Intel Core 2 Duo Macbook Pro with 3 GB of 667 MHz memory and a 200 GB hard drive. This morning, my free hard drive space was 5gb, but I noticed some time later that it had dropped clear down to under 100mb, with minimal applications running. It continued to fall until I panicked and started deleting media files to get my free space up to 10gb. Searching different forums online, I found that many have had this problem before, but no one really offered a solution that has worked for me. I tried downloading OmniDiskSweeper to see where the free space was being eaten up from, but that didn't offer a clear answer. I then tried deleting several Spotlight preferences in both of my Library folders and restart, but that also didn't solve it. One thing I have noticed is that the less amount of applications I am running, the slower the decrease of space is, and vice versa. I also read something saying that as a rule of thumb, you should keep at least 15% of your hard drive space free for maximum performance of your computer, which is nice to read and I plan on freeing up at least 30gb, but I'm wondering if this could be the reason for the constant decrease. My primary goal is to stop the leak, so to speak. Any suggestions are appreciated, thank you guys so much! Let me know if any further information is needed.

G'day and welcome to the forums.

Even 10GB will present problems as the suggested free space is 15% of the drive capacity. If you are into music and photos, suggest you consider giving iDefrag a look at. Mac OS X has always been said to not need defragging, but huge storage amounts of iTunes and iPhoto has perhaps changed all that.

I think we need a few things cleared up to fully understand your problem. Are you saying that when using your computer you are slowing losing disk space but when you restart your computer it is back to normal? Since you said that you lose disk space slower when you use less applications seems to indicate that you are talking about virtual memory.

Open up Activity Monitor and click on the System Memory tab and see if you are using up all your RAM. Also look to see if you have any Page outs and Swap used which is a pretty good indication you are using virtual memory on your hard drive. If you didn't know virtual memory uses your hard drive space temporarily when you use up all your RAM. If that is the case then you need more RAM or don't multitask so much. Leaving enough empty hard drive space is a good idea in general though so that should be your first priority.