Most of the advice I can see is about moving all account related data from one profile to another new profile. That's not what this is about, I think that it needs more granularity on what is copied but I can't find an explanation of how the indexing of folders is done so I'm a bit limited. Don't care if the solution is file copying or if there is a nice addon to do the job. Background. Old account closed due to no more service from provider. Large mail file with thousands of relatively unmanaged emails. IMAP synchronisation between other online accounts was problematic so only solution available in the time was to make a complete copy to local folders. This took a few days due to the manual copy being limited in number of emails that can be copied at once. The user is starting again with a new account and a new email provider. Management is now easier and so far being done. The objective here is to use Thunderbird as the client again and provide access to all old emails (for both content and email addresses) but do so in such a way that the user can't confuse the two, so some separation is required. The old profile had multiple accounts, only some of which were required in the new setup. What I need to do therefore is to move a subset of the local folders in one account on machine A to either: a) (Ideally) A set of local folders in a dedicated profile on machine B so that the user has to use profile selection at startup to deliberately select the relevant local folders to access them. - A bit like having to visit the filing cabinet in the other room to retrieve something. I realise this makes it harder to cut and paste old content within Thunderbird, but that shouldn't be an issue with the predicted amount of times this will be required. b) A subset of local folders in the user's new profile on machine B. (In effect copy some of the local folders from machine A to machine B but different profiles) This would make the cut and paste easier but also might not be as clear to the user about what is old and more importantly I suspect is not easily doable with just file copies. I suspect this was what this question was asking - https://support.mozilla.org/en-US/questions/1206937 but there wasn't a response to this one and it's the only one Ive found to date that doesn't talk about moving the whole profile. Thanks for any pointers. I appreciate that this is free software in all senses of the word but I am surprised that there isn't something in the product a bit more than the profile manager to ease handling of backup and restore between users - simply because the rest of it is so well thought through and well implemented (At least as far as a user can tell).