Outlook 2003 Auto-Complete Cache (History List)

When you begin to type an email address in the TO: field, Outlook looks into the history cache and creates a dropdown list of email addresses, contacts or exchange names to match. It holds the last 1000 used addresses. New names are not added until the current outlook session ends and outlook is restarted.

How to Delete the Entire History List File

If you find too many of the addresses in the history are malformed or you wish to move a history list from one computer to another, you can find the file in the following location: C:\Documents and Settings\username\Application Data\Microsoft\Outlook\<profile_name>.NK2
You will have to have hidden files and folders disabled in folder options to see the application data folder.

How to Remove Individual Names from History List

1. Begin typing the name of the name you wish to remove in the Outlook TO: Field in a new message.
2. Use the arrow key (not the mouse) to select the incorrect name.
3. Hit the Delete key (not Back Space). This will remove the name from the history list.

How to Change the Maximum Names in the History List

1. Click Start and Run. Type regedit, and then click OK.
2. Find the key: H_KEY_CURRENT_USER\Software\microsoft\Office\10.0\outlook\
3. In the right pane, right-click and select New, then DWORD Value. Name it: MaxNicknames.
4. Double-click on the key and type the number of entries (in the value box) you wish to have as the maximum. The Default is 1000.