Macbook hard drive mysteriously filled

[trenonotte]

Long time MacRumors reader, first time poster...

Problem: While browsing the internet on my macbook tonight, an OS dialogue window popped up stating that my startup disk was almost full and I needed to delete files. A glance at a finder window showed that instead of the 5.5 GB free I had earlier in the day, I now had about 200 MB free, and that amount was rapidly dropping. I emptied the trash and restarted, after which my hard drive showed about 415 MB free.

The only thing I downloaded and installed in this time was Silverlight for mac, so I could watch video on the NBC olympics website.

My systems specs are:
2.0 GHz Macbook Core Duo (Purchased summer 2006)
2GB RAM
60 GB hard drive
Mac OS 10.4.11

Google searches and searches on the Apple support discussion boards didn't yield anything useful, and the only macrumors troubleshooting thread that seemed even remotely relevant scared me: https://forums.macrumors.com/threads/333494/

Any help or advice anyone can offer would be greatly appreciated. Thanks!

 

[WildCowboy]

Yep, this is almost always a runaway log file. Download OmniDiskSweeper, WhatSize, or Disk Inventory X and look for a really big file. Once you find it, you can generally just delete it. Only if it happens again is it really worth digging into the cause of the issue.

 

[ZballZ]

Download GrandPerspective.

A small freeware app. It scans your HD and gives a visual representation of file sizes. It is an awesome app to locate (and then delete) crazy-large files that you dont really need... (obviously, dont delete anything, unless you know what it is!)

 

[trenonotte]

Used grandperspective to find and delete a 5.22 GB log file. Many thanks to both ZballZ and WildCowboy!