DescentBB

I'm trying to email some large files for work but I get a 4.3.1 size limit error message. I've tried compressing the file but still does not work. Any idea how to increase the size limit or do I have to split the file (hard, as it is one large pdf file)?
Thanks

Thunderbird is not the culprit, it's your email server I suspect. Do you use your ISP's or one of the free services such as gmail? What is the size of the file? Have you tried compression software?