Thunderbird 16.0.1 filling disk space

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?


Your issue is certainly related to a regression introduced in TB16 and which impact some IMAP servers (like dovecot).

Bug 803843 - IMAP mailfiles keep growing to gigabyte size


Have you tried this : http://kb.mozillazine.org/Compacting_folders

Because this article is for old Thunderbird versions, you will find the option here: Edit / Preferences / Advanced / Network & Disk Space. Also it is turned ON by default with this setting: Compact all folders when it will save over 20 MB in total.

If not give it a try. What I think that you are victim is that thunderbird may have a little bug that doesn't clean well his folder.

IMAP is quite complex and what is happening is that your e-mails are on the server but downloaded to your mail client.

If it's on his default settings then thunderbirds must delete what has been deleted from the server. that part may have some trouble.

Best regards,


I had exactly the same problem. I made some space in my home and thunderbird ate it all. Compacting was not possible ("No space left on device" it kept saying). My "ImapMail" folder had more than 20GB!

I found out that in one of my email account imap folders were files INBOX (7.3GB) and Sent (8.6GB). I closed Thunderbird and then moved those two files to my external hard drive (as backup). After openning Thunderbird again it created new files, which had been moved, and now they have only few kilobytes. I haven't lost any emails and everything works as before.