Hi Please could you upload a screen shot of the filter you created? There might be an error we can see. Just a thought - you can set an auto-reply in your webmail, and one in Thunderbird. The webmail sends the auto-reply when the incoming email reaches the online server, then Thunderbird sends another one when it downloads the message and runs your filter. Not actually the same auto-reply, but they may look alike. Hope that helps, Agnes