See https://support.mozilla.org/en-US/kb/switching-thunderbird#w_importing-from-outlook-and-eudora

The import wizard apparently is broken in recent versions of Thunderbird, so try the old version linked in that article. Uninstall the current version first, then install the old one, do the import then update to the latest Tbird release.

The import wizard in current versions will crash if 'Import everything' is selected instead of just 'Mail':

https://support.mozilla.org/en-US/questions/1247226

Thunderbird is crashing even when just importing 'mail' too. Already tried that. Instead of all I imported my address book individually, or contacts, and that worked. But importing just mail is not in the latest version as you say. Where would I go to get an old version? And does that mean I will have to go through setting up all 4 of my email address each time? Doesn't seem like a very practical thing to do. That was a lot of work. And what about the emails already downloaded into Thunderbird from email addresses I've already set up and received email in? Thanks.

I think I would rather try the MailStore Home approach instead of uninstalling the current version and losing everything I've done up to this point with 4 email addresses to install an older version, import, then upgrade to the newest. Your thoughts? Thank you.

Tony said

I think I would rather try the MailStore Home approach instead of uninstalling the current version and losing everything I've done up to this point with 4 email addresses to install an older version, import, then upgrade to the newest. Your thoughts? Thank you.

I don't see why not if it will save you all that trouble.

Uninstalling and re-installing or upgrading doesn't affect your data in the profile folder. If you want to try the import wizard with an older version, TB 17 is often recommended. All versions of TB are available here. But I would try the MailStore method first.

You CAN get TB to import your old emails using an older version. Trying to update to the newest version fails though. It only goes up to version 45 and refuses to install anything higher. I used the downloaded install file to force it, and it removed all my old mail and filters, keeping only the contacts. This is not a problem they are willing to fix. Maybe there's a reason, but no explanation is forthcoming, is it?

You CAN get TB to import your old emails using an older version. Trying to update to the newest version fails though... it removed all my old mail and filters, keeping only the contacts. This is not a problem they are willing to fix. Maybe there's a reason, but no explanation is forthcoming, is it?

Use the old version to import, uninstall the old version, then download and install the new version. Backup your profile before uninstalling the old and installing the new version. If the new version doesn't outright load your profile, use the profile manager to restore the back up profile. If all else fails, manually copy the mbox files from the backup profile local folders to the new profile local folders.