Open Outlook on your computer and click on the File option placed at the top-right corner. If you experience problems such as Outlook 2016 search not working, you can rebuild the index. Continue the process by clicking Search on the left-hand side, followed by clicking the “ Indexing Options “ button. Click on the Advanced button. Lastly, click on the Rebuild button. Wait till the rebuild process completes and then restart your Outlook to check if the problem is resolved.