Review for Duplicate Contact Manager by Reinaldo Augstroze Rutter
Rated 4 out of 5 stars
Very good indeed. Thank you Marian! I agree with others users about instructions on how to use it. I found out just by applying logic. Once you install it you have to restart Thunderbird. Then go to Adress Book / Tools/ Find and manage duplicates. Hope it helps.
To create your own collections, you must have a Mozilla Add-ons account.