When Thunderbird suggests email addresses for me as I type, there are many addresses there that I know are obsolete. How can I permanently remove them so they are never suggested to me again?
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This one is about as counter-intuitive as it gets. The trick is that you don't delete auto-complete entries from the main Thunderbird window -- you delete them from the autocomplete cache as accessible from within a new email.
- Turn auto-completion on
- Open a new email
- Within the email window, click the Contacts button (should create a pane at the left with the list of addresses)
- Delete the entry you don't want.
I've done this successfully on my machine.