The version that transferred to the new machine worked briefly then generated an error message to trash the application. I downloaded a new version and now I can't get things back the way they were. I had several e-mail accounts and 20 years worth of old e-mails saved in various folders. It's all gone. I tried the copy Thunderbird folder from old machine's profiles and paste on new machine in same location, but that didn't work. What now?? Thanks.