If you have Contacts in Microsoft Outlook's Contacts folder but they are not accessible when you click on the To button, check these settings:
Are you using the "wrong" view?
Is Name Only selected at the top of the Address book dialog? When More Columns is selected as the Search option, the address book will only display names if you search.
Is the expected address book set as the default address book?
- Open the Address Book using the Address Book button on the ribbon
- Click Tools, Options
- Which contacts folder is selected in When opening the address book, show this address list first?
Is the Contacts folder enabled as an Address Book?
Make sure the Contact folder is enabled as an email address book.
To do this, right-click the Contacts folder, choose Properties then Outlook Address Book.
Is the box to Show this folder as an email address book checked?
In Outlook 2013 and up, the Show folder as an email address book should be checked and grayed out for the default address book. If you have Microsoft Exchange accounts in your profile, each Exchange account's default contacts folder will be enabled as an address book and grayed out.
If this is grayed out (but not checked)...
If this is not checked but grayed in Outlook 2013, Outlook 2016, or newer, you'll need to make a new profile to fix it.
If you are using Outlook 2007 or Outlook 2010 and the checkbox is grayed, you'll need to remove the email account and re-add it or make a new profile as you can't remove the Outlook Address Book service in these versions.
...and you use Outlook 2003: Go to Tools | Email Accounts, choose View or change existing directories or address book. Is the Outlook Address Book present? If it isn't listed, add it and close and restart Outlook. If it is listed, then remove it and close then restart Outlook and repeat these steps to add it.
Remove Account from Outlook 2007 and newer
If the solutions above do not fix the problem, your address book may be corrupt. You may be able to fix it by removing all accounts from your profile if using Outlook 2010 or newer and adding them back, otherwise, you'll need need to make a new profile.
In many cases its better to make a new profile because a missing address book service means the profile is corrupt. This is especially true if you used Windows Easy Transfer to move the profile from one computer to another. Taking the time to make a new profile now may save you a lot of time in the future.
Go to Account settings, Email tab and select the account. Click Remove. Click Add and recreate the account.