Problem: You already told Norton to stop scanning your email, yet it continues to scan it! You thought you disabled the e-mail scanning part of Norton, but neverthless a small window keeps popping up at the bottom of your screen saying Symantec is scanning the message(s). You may get a message saying "Your email message to <email address of recipient> with the subject <email subject> was unable to be sent (1003,9)". Or you may get some other sort of error message. Or you may not get an error message and your outgoing mail may just not be getting delivered despite going into the Sent Items.

Solution: You may have disabled one part of Norton that was scanning the messages, but Norton Internet Security has many components which could be scanning the email. You will need to disable all of them in order to be rid of this menace.

1. Open Norton Internet Security. To do this: Down at the bottom of your screen you should have a yellow thing for Norton. Click on that. That should open Norton Internet Security.
   
2. Click on the Options button, and from the drop-down menu choose Norton Antivirus.
3. In the Norton AntiVirus Options window, on the left-hand side, under Internet, you should have the word "Email". Click Email.
   
4. Uncheck both Scan incoming email and Scan outgoing email.
5. Click OK.
6. If a message comes up warning you that this decreases your computer's security, it should have a box containing "15 minutes", which indicates how long you want to turn it off. Change "15 minutes" to "Permanently" and click OK.
   
7. Click on the Options button again, and this time from the drop-down menu choose Norton Internet Security.
8. Click on the Email tab. Under Email scanning, uncheck Show Tray Icon, and also uncheck Progress Indicator. Also uncheck "Use Outgoing mail to train spam engine", if present.
9. Click OK.
   
10. Click on the Options button yet again, and this time from the drop-down menu choose Norton AntiSpam.
11. In the middle of the window, uncheck "Turn on Norton AntiSpam". Now it says Norton AntiSpam is off.
12. On the left side of the window, under Email, click Filtering
13. Uncheck "Use outgoing email to improve Norton AntiSpam filtering".
14. Click OK.
15. Now we're back on the main Norton screen, and there are a series of items with green check-marks or red X's. One of these items is Privacy Control. Click on Privacy Control and a pane will appear to the right side of it with a button labeled "Turn Off". Click that Turn Off button.
16. If a message comes up warning you that this decreases your computer's security, it should have a box containing "15 minutes", which indicates how long you want to turn it off. Change "15 minutes" to "Permanently" and click OK.
    
17. Close the Norton window.
    

This should disable everything in Norton Internet Security that I can conceive could be scanning the email. Often just disabling Norton altogether using the disable option in the taskbar icon's menu won't stop it from scanning the email, incredibly (and frustratingly!) enough. But follow this comprehensive disabling regimen and the scanning should stop, along with whatever complications the scanning may have been causing (server time-outs, error messages, inability to send messages with attachments, etc.).