A load of stuff has occured since version 2.0.0.23

I think it would be better if you gradually updated even if that sounds like a real pain.

This link will get you to where all the old downloads can be located. http://ftp.mozilla.org/pub/thunderbird/releases/

This link is the version 2.0.023 http://ftp.mozilla.org/pub/thunderbird/releases/2.0.0.23/

If computer is Windows OS, then select 'win32' option. Then select the prefered language eg: en-GB = English British Then click on the 'Thunderbird Setup 2.0.0.23.exe' to download.

As you have tried to force it to use 78, you may need to force it to be backwards compatible. So install, but do not launch Thunderbird. You have to start it a bit differently the first time.

In Windows search / menu select 'Run' and choose the Run app type : thunderbird.exe -p --allow-downgrade

Note there is a space before the -p and also after it. Then press Enter. This will launch Thunderbird 2.0.023 with permission to launch the profile you choose.

Thanks ever so much--Will tackle over the weekend and hopefully will solve issue Much appreciated

I installed the Thunderbird 2.0.0.23 version from the link you provided on my new computer and I have copied the old default profile to the new machine into the profile directory. But the old profile does not load and if I delete the newly set-up default profile and replace it with the old default profile and try to launch T-Bird, I get an error message <"an instance of Thunderbird is already running. Close it or re start your machine"> Any suggestions? Thanks PS I have close to 9,000 emails in about 10 custom named folders in the original app profile on the old machine--those folders just don't show up in the new install on the new machine