Outlook for Mac 16.91 Search

Rebuild the Spotlight index on your Mac

Rebuild the Spotlight index on your Mac - Apple Support (CA)

Have you tried contacting Microsoft Support about this issue yet? ... and, if so, what was their recommended solution?

Regardless, if Spotlight isn't indexing Outlook's data correctly, searches may not yield expected results.

To address this, you can try rebuilding the Spotlight index for Outlook:

First - Add Outlook to Spotlight's Privacy List

1. Open System Settings and navigate to Privacy & Security.
2. Select Spotlight and then Privacy.
3. Click the '+' button and add the folder where Outlook stores its data. This is typically located at ~/Library/Group Containers/UBF8T346G9.Office/Outlook.

Next - Remove Outlook from Spotlight's Privacy List

1. After adding the folder from the previous step, wait a few minutes.
2. Then, select the folder in the Privacy list and click the '-' button to remove it.

If the problem persists after reindexing, consider the following steps:

• Update Outlook
• Check Folder Visibility: Verify that the folders you're searching within are not hidden or excluded from search.
• Rebuild Outlook's Database

As another option, If searches work properly in other apps but just not in Apple mail, you could try the rebuild option.

Mail > Mailbox > Rebuild

Sorry.. I misread the OP's question. Please disregard my response. Outlook......not Apple mail.