Set Outlook 2007 as the Default Mail Client View The Full Article To use Aid4Mail or Transend Migrator, Outlook 2007 needs to be the default mail application. Here are the instructions to achieve this: 1. Open Outlook 2007 2. Click Tools, then click Options 3. Click the Other tab 4. Click Make Outlook the default program for Email,Contacts, and Calendar. 5. Click OK and return to your previous task.