Are we sure it's OE that's sending those multiple messages? Do the multiple messages appear in your Sent box?

It may be your ISP, or its network, doing something odd.

It's common for servers to re-send messages whose download the server thinks was incomplete.

Did I understand right that NONE of the message you sent from Comcast Webmail were duplicated? That would shoot down my idea.

I had the same problem!
The Send Items.dbx file has reached the file size limit (2 GB) that the Outlook Express can handle it.
After send the email, OE can't copy to Send Items folder the mail that was send, and the mail stills at the Outbox folder.

All my steps to solve this problem:
- To backup mails inside the Send Items folder, I create a new folder and copy all mails to this new folder;
- Exit Outlook Express;
- Delete Send Items.dbx file;
- Start Outlook Express (OE Will create a new, and empty, Send Items.dbx file).

Tiago Lages

That same thing is starting to happen with my phone!

To PrairieGirl:

Your solution of un-checking the break apart messages button worked for me... Thanks!

The Sent folder for us was over 2GB. The answer to move and recreate the Sent items folder did the trick. Thanks.