Startup Disk automatically filling up!

[muss87]

Hey Guys,
Weirdest thing is happening to my MBP.
I keep getting the startup disk is full message. So go check and sure enough my HD is totally full with like less than 100mb left. So I then go and find some big files and delete. All good. I have like 3-4GB free now.
BUT then like 1 minute later the message returns and it's back to less than 100MB left on the HD! what?!
So I'll reset and then when it comes back on i've got like 30GB free! and then it just starts filling up again! and I can watch the free space disappearing!
What is it!? I havent installed anything weird.
Plus I had an old iMac that once did this in snow leopard. Never figured out why.
I'm so confused and frustrated!
And ideas!?
I've verified the disks, but it all came back good

 

[gsahli]

Cases of this I've seen (may not be all the cases...) are caused by some real software/hardware error that is causing the error and/or message logs of OS X to fill the space.
Go to the Console Utility and read the logs to see if there's an error being recorded many times per minute (100's - 1,000's of them).

It is not unusual to have OS X use 15-20 GB of disk space for "swap" space, especially if you do audio-video-photo editing.

Use the Activity monitor (utility) to see what it reports for page-ins/outs, disk and memory use, and look for runaway processes.

 

[kasiadkaminska]

i'm having a similar problem. start up disk filling up constantly.

have checked console and do indeed have 4000 messages literally in the last half an hour since switching my laptop on.

what do i do from here?

 

[harryb2448]

Any chance you have activated Time Machine and it is saving to the hard drive?