In message , Frank Slootweg
writes:
Paul wrote:
[...]

I don't know a thing about this, whether it'll work or not. I
would suggest backing up all materials before attempting anything fancy.

https://addons.thunderbird.net/en-US...xporttools-ng/

FWIW, I've used (an earlier version of) this software to import my
(exported) email from Windows Mail into Thunderbird. Worked fine.

For that, I'd need the old system to be running, so I could tell it to
do the export.

[It's a pity - IMO - that email softwares don't store emails as
(individual) real files in real folders. I realise that, in the early
days (of PCs at least), considerations of size (such as cluster size
when most emails were under 1K) and just plain speed made using single
mailbox files, and so on, necessary, but we passed the point where that
mattered, some time ago; but by then things were well established, and
nobody ever started over, there always being more interesting things to
do.]

By importing the exported mail from the new profile into the
(recovered) old profile, the new mail should be merged with the old
mail.

An even safer method would be to export mail from both the old and
new profiles and then import them into a third - even newer - profile.

That way, if you keep backup of the old and 'new' profiles, you can
always go back in case anything goes wrong.

[...]
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

Everyone learns from science. It all depends how you use the knowledge. - "Gil
Grissom" (CSI).