Do this. You are on the right track. If you want to do this in thunderbird, install the importexporttools addon and do these steps: - highlight each folder to save - rightclick and select importexport option to extract mbox - repeat for each folder - next, highllight Local Folders - rightclick and select importexport option to import mbox - repeat for each folder

you can also do this from windows file explorer when thunderbird is not running by copying the message folders from the account and pasting into Local Folders folder.

In case it is important, I should have said my System Is UBUNTU 24.04.1 LTS

I installed "importexporttools NG". I was told that "importexporttools" was not suitable for my version of TBird.

This time, when I selected Export, it gave me a list of the accounts and a Save button. I right clicked on the account but there was no option for importexport. I selected the account and then Save. The window showed the export to a zip file 0-100%. When it got to 100%, TBird hung and after a few waits, I restarted Tbird. The zip file is 25.9GB which looks like the whole TBird database!

I am wondering about rebooting the whole PC? I'll do that and come back here to report any change.

That export is NOT what you want. And I wouldn't trust it anyway. Mozilla recommends not exporting more than 2 gb, and that export is always problem-prone. To save what you want, exit thunderbird and access the profile from Linux file manager. I am no Linux guru but I think profile is .thunderbird and what you want is in the Mail\<accountname> folder - inbox, sent, etc. Copy them and paste into the Mail\Local Folders folder while thunderbird is not running and then restart thunderbird and I think they will appear - ignore the msf files, as thunderbird will recreate them.

Thanks for that! I know UNIX so hopefully no problems there!

Do you think I should remove that addon?

I'll do what you recommend and get back to you.

If the addon is not recommended, I would remove it. Otherwise, it can be very useful in exporting and importing folders.

OK, that worked! I used the Terminal for UNIX commands as the UBUNTU file manager couldn't see beyond the "hidden" directory .thunderbird.

A thought does occur in that all the emails in my account are already held on my hard drive, so, when the email account disappears they won't disappear from there, will they? Therefore, I don't need to move them to the Local Folders area???

You're correct. What is iikely, though, is that thunderbird may keep attempted to download mail from the account and that may generate error messages each time that there is a problem with the account. If true, that will become annoying quickly. Otherwise, there would be need incentive to move them. I defer on the file manager commands. I have a Mint setup and the .thunderbird folder is fully accessible, but I avoid any specifics, as there is so much I don't know there. :) I'm glad it all worked for you.