If you have Windows Vista, you may be using the AutoComplete feature to enter information into email addresses. The AutoComplete feature works great when you are typing in a name or address, but it can also be used to enter other information when you are trying to complete a task in Outlook. One problem with the AutoComplete feature is that it can mistakenly enter wrong information when you try to complete a task in Outlook. For example, if you type “John Doe” into the AutoComplete field in Outlook, Outlook will automatically fill in “John Doe@contoso.com” as the correct email address. This is a mistake because “John Doe” is not an email address! To fix this problem, you can use one of two methods:

  1. Edit the AutoComplete entries so that they are only entered for email addresses that are actually valid email addresses. To do this, open your Control Panel and click on the Add/Remove Programs button. Then select Outlook from the list of programs and click on the Edit button. In the editor window that opens, change the value of “Email Address” to something other than “John Doe@contoso.com”. For example, if you want to enter an email address that is not associated with a computer account, change it to “user@company”. Now click on OK to close the editor window and return to your originalAutoComplete entry.
  2. Disable the AutoComplete feature altogether and then try again when you need to complete a task in Outlook. This approach works best if you do not use Outlook often and don’t want to risk having your incorrect email address entered every time!

First, you can use the Down Arrow key to select the incorrect entry in the list, and then use the Delete key to remove the entry.

This usually works, but for some people it just doesn’t work, the wrong addresses come back. What you can do is completely wipe the auto-complete cache in the registry. Start by completely shutting down Windows Vista Mail.

Open up your registry editor by typing in regedit into the start menu search box, and then browse down to the following key:

Once you are there, look for the entries in the right-hand side. Delete everything other than the (Default) key.

Now you can restart windows vista mail, and all of your auto-complete entries should be gone, including the wrong ones.

Derived from mtnpilot’s thread on the forum.