Prevent Thunderbird from corrupting IMAP attachments
on Thursday 13th March, 2008 Gabe speculated thusly…In the “about:config” section of Thunderbird (Tools > Options > Advanced > Config Editor) look for the “mail.imap.fetch_by_chunks” and ” mail.server.default.fetch_by_chunks” values and set them to “False”.
Mozillazine gives some more information about what this value actually does here
Posted in HowTo, Information