De Microsoft . ..
Microsoft AutoUpdate for Mac, which comes with Office, can keep the whole suite of Microsoft Office software (Excel, Outlook, PowerPoint, and Word) up to date. When AutoUpdate is set to check for updates automatically on a daily, weekly, or monthly basis, there's no need to search for critical updates and information; AutoUpdate delivers them directly to your computer.
- On the Help menu, click Check for Updates.
- Under How would you like to check for software updates?, click Automatically.
- On the Check for Updates pop-up menu, click the frequency that you want AutoUpdate to use to check for new updates.
Então, de acordo com o MS, ele deve estar em execução o tempo todo, se estiver definido como Automático.