''<p>vincent.auger [[#question-1561898|said]]</p>'' <blockquote>Somewhere in my version of Thunderbird, there is an old adress of one of my correspondant which is recorded This adress is no longer valid and I have deleted it from my adress book </blockquote> If I had a dollar for everytime I have read that I would be a millionaire <blockquote> Nonetheless, when I start to write my correspondant's name, this adress keeps being proposed among the first options for the automatic completion of the adress How can I delete this wrong adress from the hidden part where Thunderbird has stored it? </blockquote> There is at least two address books and my guess is the address is coming from the collected addresses book. This is where outgoing mail addresses are saved when they are not in your address book collection. Generally this is the first address book entry folk have and latter the individual gets added to the main address book, but the original automated save remains to haunt you years later.