Been using the Thunderbird for a while now, but this only came up today, each time I replied it put my reply at the bottom of the email and not the top, but it only started today. Searched all through the settings, and I couldn't find squat.

1. In Thunderbird: Go to "Account Settings"
2. Select "Composition & Addressing" for the account in question
3. Check the checkbox in the Composition group that says "Automatically quote the original message when replying".
4. Once the combo box below is enabled select the option "Start my reply above the quote"

[ Replies Append to Bottom in Thunderbird at Elliot Lee ]

That proves it, my old settings had been imported from Outlook Express, and it was smart enough to duplicate that behavior. I had removed and readded an account today, and it picked up the default, which is a crazy "reply after" that would force everyone to scroll to read the new part of the email.