I've never gone through this particular procedure myself, but I think there is a step missing. Step 1.5 Select a folder in Thunderbird into which you will import the eml message files. I'd suggest creating a new subfolder under Local Folders for this. I think that any folder inside a POP-connected account would work too, but I'd be unlikely myself to have an account that uses POP. I'd avoid a working IMAP-connected account because Thunderbird will set about synching to the server and I'd prefer it did just one thing at a time. So, import the data, and then reorganise it.