If the old computer is still available, I recommend redoing the transfer: TRANSFER::: Here is the link for moving a profile in Windows when installed in default location:

https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer

here is the info in brief steps:

1. ensure thunderbird is not running on old machine
2. enter %appdata% in search window on task bar and press Enter key
3. this should open windows file explorer in Appdata\roaming folder
4. highlight the Thunderbird folder and copy to external media
5. ensure thunderbird is installed on second computer and NOT running
6. enter %appdata% in search window on task bar and press Enter key
7. you should be in Appdata\roaming folder , copy&paste the exported Thunderbird folder there. This may prompt to overwrite an existing folder of same name. allow it
8. start thunderbird and all should be there

On your question, yes you can restore a local folder: - install the addon, importexporttools NG - highlight 'Local Folders' - rightclick and select importexport option to import mbox and then locate and select a folder you want to import - repeat the above for each such folder

Thanks very much David

You are very welcome. :)

I got there in the end, for what it's worth as follows-

• The tip about the "importexprttools" addon was very useful as it has enabled me to run a timed backup of Thunderbird, which is one of the things I wanted to do.
• I did try to run the export, import routine from this addon but ran up against a message saying that the export filename wasn't valid on the importing machine, I'm not sure what this might be, perhaps something swapping from a Windows 10 machine to Windows 11? I did try renaming the file to a format that appeared to be right, but no luck.
• I then ran the full routine (outside the app) for moving the profile again and still could not see the single local subfolder I was missing on the new machine.
• By now I was getting more familiar with the file layout within my local subfolders directory so I copied the two appropriate entries from the old machine and pasted them into the folder on the new machine. Restarted TB and all is well.

Phew. Thanks for all the contextual help that's been posted here, I wouldn't have dared to to start editing parts of my profile without it- in fact I didn't even know I had a Profile a week ago.