Reset the user's password so that they do not have the credentials to login.

OR

Remove the user's permissions:
  1. Go to Administration > Set up system security
  2. Open the user account
  3. Remove the groups selected in the "member of" box
  4. Click OK to the following message: "This user has not been given any group rights. The user must be a member of at least one group before they will have access to the system."
  5. Click Save and Close on the user account
  6. Now when the user tries to login, they will receive the following message: "The system administrator has not given you security rights to access The Financial Edge system."