Your outlook is about end of functional life so it is of little use going forward. It could even be it is so old it is not communicating with Thunderbird as expected. To get meaningful results, a log would probably be required https://wiki.mozilla.org/MailNews:Logging

I would say your CSV import failed because you did not align the field names used by outlook to those used in Thunderbird. The import dialog offers the interface, but an amazing number of folk click through that and expect the computer to it out and it does not. It guesses and guesses very wrong a lot.

I wrote a blog post in 2013 about what I consider essential "data massaging" to be done when a CSV file is involved. https://thunderbirdtweaks.blogspot.com/search?q=csv Nothing much has changed in the intervening decade as the CSV format predates personal computers, other than Thunderbird user interface for import has been significantly improved and the field name may have changed when Thunderbird address book was converted to the card book standard.

The field names Thunderbird "expects are; First Name,Last Name,Display Name,Nickname,Primary Email,Secondary Email,Screen Name,Work Phone,Home Phone,Fax Number,Pager Number,Mobile Number,Home Address,Home Address 2,Home City,Home State,Home ZipCode,Home Country,Work Address,Work Address 2,Work City,Work State,Work ZipCode,Work Country,Job Title,Department,Organization,Web Page 1,Web Page 2,Birth Year,Birth Month,Birth Day,Custom 1,Custom 2,Custom 3,Custom 4,Notes

These do not have to be present, but if your file is using other names, making them the same in LibreOffice will vastly simplify the import.

I'm sorry Matt. I am computer challenged. I don't really understand about creating a log. As for the names. outlook 2010 imported the address book to an excel file. The excel file has all the right names in the headers and all the information in all the right places under those headers. With the TB import tool, when I am choosing what to display: name, address, etc., I do not see any information for the first contact other than first name, last name and that is all that shows up in the new address book in TB. No matter what I choose in the drop down boxes for addresses or emails, nothing shows up. I appreciate the help more than you could know. If there is anything else I could try that my 'computer challenged' mind could handle, I'm willing to try. Would it be possible to set up a Google mail account, import the contacts to that and export them from there to TB? Thank you, Dave Frank

In my blog post I talked about the total inability of the excel version at the time to not scramble the data. What is saved was in a very old text format that was by then largely only supported by Microsoft office (ANSI). After Excel has screwed up the data, you have to open the file in Notepad on windows and use save as to convert it back into usable UniCode text.

I understand the latest versions of Excel can manage to open a unicode file without messing in it's nest, but I have not used a version later than the 2016 one I use to develop macros for my wife.

I will offer you a deal. Send me the CSV file to matt_au at gmx dot com (I assume you can make that into a real email address) and I will check it out and do what I can to simplify the process.

Matt, I downloaded Libre today and was able to open the saved .csv file that I exported out of Outlook 2010 with Calc. I changed the heading names to match the import list in Thunderbird and saved it with a different name. Praise God, it worked. So, thanks for all the help, Matt. I really appreciate it. I'll delete your email address on my end so you won't have to worry about anyone else getting it. Dave Frank

Sorry Dave, been out of town for a few days and got home last night. Pleased you got things working, I did start the import before I left and in the process found a bug in the daily release that I am yet to file. So I guess we are both winners.