TRy this:

Menu app icon > Help > More Troubleshooting Information Under 'Application Basics' - 'Profile Folder - click on 'Open Folder' A new window opens showing the contents of your profile name folder.

Exit Thunderbird now - this is important.

Scroll down, locate and delete this file: pkcs11.txt

Start Thunderbird If requested, type password at prompt and select the checkbox for Password Manager to Remember password. Then click on OK.

Check 'Preferences' > 'Privacy & Security' > 'Passwords' section Click on 'Saved Passwords Click on 'Show Passwords'

Are passwords now being saved?

Very many thanks. I checked but this file pkcs11.txt does not exist in the profile folder. I also checked my previous install on another laptop and again its not there. However I found a copy that was about one year old in a back up and I copied this to the profile folder on my new laptop and restarted Thunderbird and guess what it works. Can now save password and when I check saved passwords in preferences I can see both the server and outgoing server passwords are now stored.

My assumption is that this file (pkcs11.txt) is not being automatically created post install?

Very many thanks for the excellent advise and knowledge. Mike

re : My assumption is that this file (pkcs11.txt) is not being automatically created post install?

It's odd that it was not in the Thunderbird profile on old laptop. You would have expected to have the same password issues.

It's odd that upon start of Thunderbird on new laptop that the file was not auto created, because usually it can be deleted and auto receated. When moving between different OS, it is necessary to delete that file.

It might be a good idea to create a backup of the current Thunderbird folder that contains the 'Profiles' folder.