If you cannot find the path "Outlook > Preferences > Search" you're probably using Outlook in "Outlook Legacy" mode (instead of the "New Outlook"). So, the step 3 described in the solution by AlexChen is not available.
3. Check your search settings: Make sure that your search settings are configured correctly. Go to Outlook > Preferences > Search and make sure that the correct folders are selected for search.
In my case (Ventura/Outlook 2016) the following steps fixed the issue:
Step 1) Type the following command in your terminal:
sudo mdutil -a -i off
sudo mdutil -a -i on
Step 2) Re-Index your HDD:
- Open System settings and select Siri and Spotlight.
- Scroll down and click the Spotlight Privacy.- From the Finder menu select "Go > Computer".- Drag the Macintosh HD to the Privacy tab and wait for some time.- From the Privacy window, select the HD and then click the minus (-) button near the bottom left of the window.
Step 3) The strangest one:
From Outlook do this: Enable && Disable "New Outlook" Feature
I know, I know... step 3) seems like an absurd step (activate the option and then deactivate it immediately afterwards) but thanks to what seems like a nice function of the new outlook, step 3) is mandatory for the success of the procedure
That's it.