Source Disk becomes full when cloning

Hi,

I'm trying to clone the startup disk of my MacBook Pro. It's a 320GB drive and I had 23GB free space on it when I started the cloning.
After about 50% into the cloning (according to the progress bar) my startup disk (also source disk) is completly full, I have 0 KB left on it. At this point CCC stops cloning.
Closing CCC makes the space free again… Another try - same result
Managed to free up some additional space, so I now have 32GB of free space when starting the cloning. At this very point I'm quite sure it's going to happen again as I can see the free space is getting lower and lower by the second.
To me it seems like there some caching issue…?
Not sure if it helps to say that it seems like it's happening when the cloning gets into the directory: /Library/Application Support/TrendMicro/common/lib/vsapi/tmp/
This is a directory that is unavailable to me, even though I'm the admin. The lib directory is the last I can open, vsapi is locked.
And sure enough, by the time I wrote this I'm out of space on the source disk!
I'll try to remove TrendMicro Security to see if it makes any change.

Otherwise, any ideas??? :/