When you add a contact to an address book, the file gets updated, so last update will be the last contact added or last contact modified. Each contact is not a separate file, so it is impossible to search by modified date or created date. Thunderbird stores contacts in sqlite files in profile name folder. If you export an address book as .csv then it is a newly created file, so computer will give it the created date.

Suggestion moving forwards.

You would need to use an unused field and then keep to a format. In Contact details there is a place to add 'Fax' or 'Pager' - if you do not use those, you could use it as somewhere to store a date eg: 2022 10 25 ( representing 25th Oct 2022) as number format is expected. Only you know that eg: Fax actually stores the date you added the contact. Then you could select 'All Address Books' , enable the 'Fax' column header and click on it to sort by fax. Or export individual address books as .csv file and then sort by the 'Fax' column header.

Thanks for your help. It doesn't help my current problem but I will bear it in mind for future.

What about just using the inbuilt sync for google address books? Or is that not possible for some obscure reason.

TBSync is only reliable 1 way, from Google to Thunderbird. I want to preserve any changes I have made since GContactSync stopped working.

TBSync is only reliable 1 way, from Google to Thunderbird. I want to preserve any changes I have made since GContactSync stopped working.

I am not talking about tbsync.https://addons.thunderbird.net/en-US/thunderbird/addon/tbsync/?src=ss

I am talking about adding the google address book as a cardav addressbook. Open the address book Then file menu > New > carddav address book. Enter the gmail email address in the dialog. No location and continue. The dialog will list the address books associated with that email account and you can select which you like.

Once the book is added, right click it (the name will be something like "address book") and select properties to be sure that you have selected the correct entry chack the link part contains the address you expect. Then change the name so you do not end up with 5 "address book" address books

Thanks Matt, that looks the same as TBSync as it creates a new address book downloaded from Google, but without preserving contact lists. But it still doesn't reflect any changes I've made in my existing Thunderbird address books. All good though, I'll stick with TBSync.