My wife is using Thunderbird on a new[ish] xubuntu 14.04 system. She has now got it fairly well configured and working the way she wants so the next step is to move her old 'local' E-Mail across.
No way is this remotely easy, I can sort of see how it might be done but there are so many gotchas that I fear it's going to be a mess.
Why can't modern E-Mail program simply use mbox (or maildir, I'm not too fussed) as they were designed rather than having to add all sorts of specially named directories and indexes?
In mutt it would be trivial!