How do I Delete All My Outlook Contacts?
Microsoft Outlook includes a contact manager you can use to store names, email addresses, phone numbers, and other contact information. If you want to clear the contents of your address book and start anew, you can select all of your Outlook contacts and delete them at once.
Launch Outlook on your computer.
Press "Contacts" in the lower-right corner of the Outlook window to view your contact list. Alternatively, you can hold down the "Ctrl" key and press "3" to view your contact list.
Hold down the "Ctrl" key and press "A" to select all of the contacts in your contact list.
Right-click one of the selected contacts and click "Delete."