Comment 4 for bug 136803

The same thing is happening when using Seamonkey mail. (SM mail and thinderbird are
close-related and share most of the code base )
When You have many messages in your mail box and you are left with no free space on drive,
then it tries to re-download all messages.
This should be (And I am sure it already has being) reported upstream,
because I managed to experience it even on M$ Windows , before I switched to Xubuntu amd64.