So this seemed to result in the outcome I wanted: - Find the old Thunderbird profile location (.../AppData/Roaming ... THunderbird/Profiles/...default/Mail/first.account.domain/Inbox - FInd the same location on the New laptop

Copy the first (old, backup) inbox to a new file in the New profile folder; I did Inbox.bak

Start TBird - and lo and behold, I have folders "Inbox" (recent mail since the old laptop crash) and "Inbox.bak" (the mail I thought was lost).

Looks like I need to add all accounts to the New TBird first so that it creates the profiles, and after that copy the backup Inbox & Sent files to the new profile folders.

This worked for me. Not very elegant, with several manual steps, but end result is what I needed.

It would be great if there was a smoother way for disaster recovery.

And yes, I should have had better backup policy in place. For everyone's benefit - I do Data Center systems for a living, and have seen far too many "backup" services which do not actually work in a restore situation. That's why my personal backups are direct file copies on large disks. It works, but leaves room for manual error, which is what happened here. Actual folders, btw, I keep where I see them - "c:\users\username\Thunderbird" - for this very reason.

EDIT I didn't see your answer, you have it covered.

Still

You could use importexporttools to import your inbox / sent folders. But do it to local folders. Don't screw up Inbox /Sent Be aware that your old mboxes might not be compacted and already deleted emails can reappear.

It would be great if there was a smoother way for disaster recovery.

You could have copied over the entire profile and be done with it. For creating backups, you should also backup the entire profile.

Thanks. Silly me;-) I'll try that next time I break a laptop (or, shortly before that).