autocomplete in Thunderbird

Question

an old and unsupported email address of mine keeps appearing in From and I dont always check which one is there so am sending people emails from this email by mistake. This email is NOT in Collected Addresses so I cant delete it from there. Can you help me? This email is for the Local Folder, that is the first one I had. Under profile, only Local Folder is there.

Answer 1

Open the menu on the top right (the three horizontal bars), hover over preferences and then select Account settings. On the left side down at the bottom you'll find Outgoing Servers. Select that and then pick your preferred email on the right and click Set Default.

You can also remove the unused old email from there.