As the very word add-in suggests, these are a set of additional applications to the default ones and help you enhance the functionality of your computer. So many times it happens that you end-up wanting additional features which are not a part of your Windows XP PC but can help you enhance your work quality and efficiency manifolds while working in Microsoft Outlook. In this case, you can rely on add-ins. Simply choose an add-in to support the desired feature and install it. But what if it is already a part of your system but you are unaware. In that case, you can follow some quick steps and detect it. You can even choose to deactivate certain unwanted add-ins and activate the more useful ones. Here is how:

1. Open Microsoft Outlook
2. Click “Tools on the menu bar
3. Click “Trust Center, and then click “Add-ins.
4. View the add-ins and application extensions that are categorized as:
• “Active Application Add-ins
• “Inactive Application Add-ins
• “Disabled Application Add-ins