Hello there neilharland. We have read your message. We try to help you.

XulRunner-platform works oke, https://www.thunderbird.net/en-US/thunderbird/78.9.1/releasenotes/

Yes the latest version of Thunderbird is 78.09.01.

A failed Thunderbird update could have resulted in a mix of leftover old and new files in the thunderbird folder afterwards, for example due to a security program on the desktop or laptop that managed thunderbird, so that Thunderbird could not replace everything. disable the security software for a while, perform a fresh reinstallation, and if the problem (persists ) stays disable the security software for a longer time.

If you start here then delete (clean) the entire directory and every profile of Thunderbird that way before the new installation start s to install it. Clean the window registry from Thunderbird and by removing Thunderbird will also clean the security software to.

Do not delete other folders, programs, etc. at that time. And do not leave any problems with maps , files and other common topics open. currently concerns software and directories.

do remove everything from Thunderbird before downloading the Thunderbird version of your choice again.(see link attached).

There is a Thunderbird profile map (page) where everything is again that is being created.

Make sure that personal topics are not deleted when uninstalling Thunderbird Software. Because then all Thunderbird profile folders will be deleted and you will lose all personal data.

https://www.thunderbird.net/en-US/thunderbird/releases/

https://support.mozilla.org/en-US/kb/uninstall-thunderbird

Greetings firefoxvolunteer

Hello Firefoxvolunteer,

Thankyou for your response. If I have understood your message I need to do the following:

1) Disable security software 2) Delete the Thunderbird directory in the Programs folder 3) Clean the Windows registry from Thunderbird, (Using a product like 'ccleaner?) 4) Ensure all other programs are closed 5) Download and install latest Thunderbird Program. 6) Point new profile to where old profile is.

Is this correct?

Regards,

Neil Harland

Just reinstall from getthunderbird.com You will loose nothing and the error will go away.

Hi Matt,

Thanks for your response. I tried what you suggested and it was successful. Top intel!

Regards,

Neil Harland

Thank you Matt. Catriona