I noticed that my "Inbox" file for Thunderbird was surprisingly large (100M+) even though there were very few emails in there and most of them were tiny. On a second account the Inbox file was 67M and that was also a bit suprising.
After some googling I came across the "compact" command which can be run on a folder from the right-click menu. After doing that, the file shrank down to 1.3M, which is much more like it. I've no idea why this isn't done automatically by default, but there you go. We do have a defrag tool after all. Might be of use to someone if they've had their mailbox for a whlie, with lots of deleted spam, especially as there's a size limit beyond which Thunderbird starts misbehaving... :unsure:/>
More info here: http://kb.mozillazin...pacting_folders