Or try this before the issue and when it happens.
http://grandperspectiv.sourceforge.net/
Hi, new here
My MacBook using OS X 10.6.8 occasionally gives a startup disc full error. On Get Info, it shows 0 space free.
Fine, so I deleted maybe 2GB of files, booted, and it showed 32GB free.
A few days later, the same happened again. Full. Reboot, 32GB free.
It doesn't seem to be linked to any type of usage.
In possibly related, possibly unrelated news, Safari runs slow and frequently requires a force quit.
So, deleting files doesn't seem to help as the disc fills up anyway, seems to be about temporary files, but 32GB is a lot of temporary file. I'm not doing anything special .. a bit of shopping, a bit of iPlayer. No file sharing, no games, not really any music.
What's my next move?
Cheers
J

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic