Discovered Accounts tab is empty when running Account Discovery.
Please browse to Management | Profile Management | to edit this discovery profile specified for the Account Discovery.
In the Delete Account Action, Select Notify via Email
In the New Account Acction, Select Notify via Email
Browse back to the Managed System | Account Discovery
Click Run Discovery Now.
The Discovered Accounts tab should show the list of accounts and request you to select which to add or exclude.
If the account is already added/excluded then when you click Run, it will not show in the Discovered Accounts tab.