locate you old profile on XP. This will be in the hidden application data folder on the XP driver, so the first thing is to enable windows to show hidden files and folders.

Once you locate the application data folder on your old drive, copy the entire "thunderbird" folder in the application data folder to your new drive, but where?

On you new computer

Windows key + R Type %appdata% and press enter.

Windows explorer will open showing whatever is your "new" equivalent to application data on XP (remote\appdata will be part of the path)

Copy the old Thunderbird folder and all of it's sub folders and files to the new machines appdata\Thunderbird folder to replace the thunderbird folder that will have been created when you installed Thunderbird and ran it.

Your data, setting and mail is now transferred.,

Note: these instructions assume you have not modified the account directories in the account settings. That is storage locations remain in their default values.

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

Matt, Thank you for the reply. I read that page in Thunderbird help, and I did not see any information about using that procedure to transfer the data from one version of Thunderbird to another version or which versions it can be used for. It looks like there are substantial changes in the recent versions of Thunderbird. Can you confirm that this procedure will work for any versions of Thunderbird?

(It would be very helpful to have this information added to that help page.)

I am very grateful for your help.

Thunderbird has had only minor changes to the actual profile data in the past 10 years, and the conversion code has been left in place for those occasions that Thunderbird encounters old profile information that requires updating.

So while folks think that changing version numbers is relevant, it is almost totally irrelevant, unless you are trying to take a new profile back to an old version. That can have unfortunate side effects, like passwords simply being lost.