How migrate Thunderbird to Mac Mail?
Currently I use Thunderbird under Lion (10.7.4), with two acounts both of which are set up as POP accounts (one is Gmail, the other a university mail account), and in both of which I leave messages on the server. I have many old messages stored locally in many named folders, e.g., under my Gmail account in Thunderbird I have folders such as:
Inbox
Mac info
Miscellaneous
Travel
Thus I am not keeping the local copies inside the "Local Folders" area.
What is a reliable way to migrate my accounts ans locally-saved messages to the OS X Mail app? And I want both my accounts under Mac Mail to be IMAP instead of POP now.
Most of the information I've found about doing this sort of thing, including on this site, is on the order of 5 years old, and some of it even involves using the Rosetta-based Eudora Mailbox Clearn, which of course won't run under Lion.
An additional complication: I already have a Gmail IMAP account in Mac Mail, which unfortunately lists all the Gmail messages I've ever received! I want to have just those that at the moment of migration are in my Thunderbird Gmail mailboxes.
iMac, Mac OS X (10.7.4), 3.4GHz Corei7, 16GB, SSD + 2T HD