Mailing lists usually don't transfer when you export and import address books in the usual way, but if you use MoreFunctionsForAddressBook to export and import in mab format, it works.

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

Select an address book, Tools/MFFAB/Actions for addressbooks/Export in mab format. On the W10 computer, open Address Book, Tools/MFFAB/Actions for addressbooks/Import addressbook from mab file. Restart TB and the imported address book should include the lists.

Thank you so much, sfhowes, I should be able to work this out now.

Okay, done. It took some back and forth, but I'm a better person for it now, and thank you again, SFHowes.

I am also trying to transfer my address book (which includes some lists) from one computer (Win7, TB 60.9) to another (Win10, TB 68.1). I tried the export/import that came with both TB 60.9 and TB 68.1 which didn't work. I then tried the addon listed above but found that the addon is not compatible with TB 68.1.

Any other suggestions?

If you copy abook.mab (Personal Address Book) from one profile folder to another, the mailing lists will be preserved. Help/Troubleshooting Information, click Open Folder to open the profile folder. Close TB if you are pasting abook.mab onto the W10 PC; the existing PAB will be overwritten. If you need to preserve existing contacts in the W10 PAB, move them to another address book by drag and drop.

If you don't care about transferring mailing lists, export an address book on the W7 PC by selecting the book in Address Book, Tools/Export, Save as type: LDIF. On the W10 PC, Tools/Import...Address books... Text file...select the LDIF file.

Excellent. That got it. Thanks sfhowes!!

But now, what with all of the failed attempts I made I now have a number of entries in the address book labeled "personal address book" on the W10 PC that are empty and I can not delete. How do I get rid of them so that the only "personal address book" I have is the one I just successfully copied onto the W10 PC?

Without knowing exactly what you've done, it's impossible to advise. On the W10 PC remove all .mab files from the profile folder, except history.mab (Collected Addresses), while TB is closed. Copy the abook.mab from W7 into the profile folder, and when you restart TB, the PAB should look exactly as it did on the W7 PC.

WOW. This took an interesting turn. So I did as you suggested here and when I started up TB it required that I re-establish my e-mail account, so I shut down TB and restored all of the profile files I had deleted and started up TB again. Again it wanted me to re-establish my e-mail account, which I did. Then I re-established all of my options and settings, then checked my address book and all of the duplicate PABs were gone and the PAB I wanted was there.

With this strange occurrence I am guessing that all is well. I hope.

Thanks for all the response. Yes, the mailing list issues are solved well enough. My most recent issue had to do with Firefox not accepting my Yahoo email site as secure, which was weird. I honestly don't remember what I did last night, probably exited and logged into Yahoo!, also bounced Firefox, and it's good. So I'm good on Yahoo! now, too. Appreciate it.