Here are the basics: # for IMAP just create in thunderbird, and all messages will be there # for POP, select each folder, highlight all messages, click tools>export as mbox # for addressbook, use the export option to create csv format # install importexporttools addon if not already done # in thunderbird, highlight Local Folders, rightclick and select importexporttools option to import mbox, do for each exported folder # setup your POP account. you now have folders in account and prior ones in Local Folders. they can be merged, but that's another task that i am bypassing here. # import the csv addressbook to thunderbird. that can be a little tricky, getting all fields aligned. That sometimes takes a few tries. I think these steps will get you started.