I'm on Ubuntu 12.04 with Thunderbird 16.0.1 and Kernel 3.6.0-030600rc4-generic. I used Thunderbird for quite a while and never had any problems with it. But now it seems to fill up my disk space very fast:
watch -n 1 df -h .
so Ubuntu started giving out warnings. First I removed some files but not much later it had filled up around 600 MB. It eats around 50 MB/min while I just download 10 emails or so via IMAP. This behaviour is new and seems to be some kind of bug. I don't want to delete my old mails, so what else could I do?