I would create a folder system under Local Folders in Thunderbird and move all the messages in the bt account into that.

One way of going about this would be to use the Archive function, but for this exercise you might have to tweak its settings to make the copy where you want it, and to ensure it preserves the folder structure.

And then remember to re-set Archiving functions afterwards so regular archiving goes where it should, and not into your bt email collection. Or maybe just re-name the Archives folder it created.

When you have emptied the bt account and have rescued all its useful content, you can remove it from Thunderbird. I would do this since it will at some time try to connect to the bt email service and give you error messages when it can't.

Make sure you do all this well before the bt service stops, because they don't have any duty of care, nor any obligation to help you once you have stopped being their customer. :-(

Thank you for reply. I have done as you advised. BUT I am stupid but how do I remove the folder from thunderbird

To remove an account:

Open Account Settings Select the unwanted account Click the button at the bottom of the pane Click Remove Account

If this selected account is currently the Default Account, you'll need to nominate another account as the default before you are allowed to remove it.

i am sorry I did not seem to have explained myself. your instruction was copy to a separate ffolder in LOCAL. one done move the folder from thunderbird. your reply stated select the unwanted account and remove. I only wanted to move my saved folder to a safe place.

Local Folders is an account in Thunderbird. It's a safe neutral space where you can store messages independently of any servers or specific email accounts. It works well as a holding pound for messages which you want to transfer between email accounts on those occasions when you can't run two accounts concurrently. I'd assumed that you wanted to continue using these messages and so you'd want them in your email client, or even in your new email account.

You could export them as files but I do think that email messages stored as text files are virtually useless. You can't follow threads, you can't do structured searches (e.g. from a to b within a specific date range).

The ImportExportTools add-on offers a range of options for exporting messages and making backups.

There are two sides to backing up; making the backup, and restoring the backup. There's little point in making a backup if you can't rescue or view its contents. If you do "remove" your old messages from Thunderbird you need to think about how you'd use them afterwards.

IMHO the best place for email messages is inside an email client. I might export selected messages to file with a project archive, but these would generally be single standalone self-contained messages recording an important request, decision or statement and probably converted to pdf for its ability to protect them against change.