MBP is losing space fast

Good afternoon everyone. I have a bit of a computer issue. I've never ran out of HDD space until now and i'm not sure where it's going. Just this morning i pulled up the "iStat" widget on my desktop and realized i was out of HDD space. so i proceeded to try and find out where all the space had magically been used up over the last week of just typing and writing. needless to say i still can't find out where, but i deleted some movies i had on my laptop and freed up about 7gigs. after this, i put my laptop down and went for a hike. when i came back and synced my iPhone to get a contact off of it my computer said there was not enough space... so i consulted iStat (and activity monitor) to be sure, and, again... while i was hiking 7 gigs magically got used up without my computer even being used...
any ideas or am i just missing something?

the odd thing about this though is that i have 56gigs of music and huge huge application folder (CS4 suite) and many many pictures... and "about this mac" is not displaying it...

since i've posted this picture (editing this post) i've lost a gig... just putting around on apples site trying to find a solution

Have you recently installed OS-X Lion over OS-X Snow Leopard? If you have, then I have had a similar (but not quite as extreme) issue. I can't tell you why it happens, but this sounds very similar to what I experienced after upgrading to Lion. The only resolution I could find was to do a complete backup of all my data-files for every software package I have, reformat my HDD and do a clean installation of OS-X Lion. For me (some months down the track now) that has worked well. It's a pain reinstalling and reconfiguring all the software again... but worth a little inconvenience rather than wait until your system crashes due a lack of space, then try to sort it all out!

I hope that's of some assistance, if indeed it is what your problem is. If you go down this route, please pay special care & attention to backing-up every data-file you have.

i'm running lion now, but there's been so software change since the OS came out... (other than system updates, but even those i haven't been getting as often as my iMac)

If you installed Lion over Snow Leopard as I did initially, that may indeed be your problem. Refer to my 1st post for the solution, which has worked for me. This is what my drive looks like now, several months after applying the fix:



hmmm... apparently the image isn't displaying... go here: http://flic.kr/p/aMt5yF

When my drive had only 10% remaining, I proceeded as described above. That image is as my drive is today, after reformatting and reinstalling. Quite a difference, I'm sure you'll agree. As I said earlier, I have no idea why this happens, but the fix works. Up to you how you proceed from here.

maybe that's the case... i'm also thinking about two other things though... i've been getting the spinning beach ball a lot lately, i know this could be because the HDD is filling up, but it could also be a failure. on that note, why would "about this mac" not see the files in their right category (i.e., music, apps, documents). finally, i was thinking it could be iCloud because i just started using this, but it only allows for 5gigs, so how could it have filled up 14 gigs already... i'll try out your suggestion, i'm just perplexed and i'd like to have it out there for the record, incase it is pertinent to this issue.