I sent an email from my office PC tp my home PC. Office uses Outlook. I use Thunderbird. The email keeps getting revceived every time I open Thunderbird, even though I have sent a receive acknowledgement to my office PC. I have deleted the message from my sent file at my office. The message just keeps being sent. Help.
There are some suggestions here: http://www.michaelcarnell.com/outlook-sending-multiple-copies-of-email/
You could also try reinstalling Outlook, but be sure your mail, and settings are backed up first.
Also what verion of Outlook are you running and are all applicable updates applied?