Apple - How do I remove Outlook mail from Spotlight?

You need to tell Spotlight not to search the Outlook Database on your local machine. Assuming you're using MS Office 2016 or later Here's how,

1. Open System Preferences > Spotlight

2. Click the Privacy Tab

3. Locate your Outlook Database which can be found in the Library folder within you home folder. So /Users/userfolder/Library/Group Containers/UBF8T346G9.Office/

4. Drag the Outlook folder into the privacy tab you opened earlier within System Preferences.

1. Open Spotlight under System settings and go to the Exceptions tab.
2. Add the folder /Users/yourusername/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile/Data/

...now everything from Outlook is excempt from Spotlight.