Howdy:
Outlook 2002:
This is how you turn it off, just reverse it to turn it on.. BTW, you could have gotten this simply by using the "Help" file in Outlook.
Turn off automatic name checking and completion
On the Tools menu, click Options.
Click E-Mail Options.
Click Advanced E-Mail Options.
Do one or more of the following:
Turn off automatic name checking
Under When sending a message, clear the Automatic name checking check box.
Turn off automatic completion of e-mail names
Under When sending a message, clear the Suggest names while completing To, Cc, and Bcc fields check box.
Murray