Using New Outlook on Windows for personal email, calendar, and contact management
Hello David Choon Siong,
Thank you for posting this case in Microsoft Community!
Based on your description, Microsoft outlook is not functioning and get bugss the search filter keep missing. I would like to cooperate with you working on this case. To clarify this case, do you mean that you are using New Outlook for Windows which getting this case? Please kindly provide us your Outlook version with product details by going to Outlook > Settings>General>About Outlook and share that entire page screenshot with hide personal information.
If using New Outlook for Windows, you may try following workaround:
- Firstly, please make sure if there is searching box showing on the top of Outlook window.
- Then you click below highlighted icon to open advanced search menu to do searching via different requirement. Please test it if working fine or not.

- Please make sure your Outlook version upgraded to the latest version. If not, you may update it and try again.
- If not working, please check this Microsoft article for further troubleshooting steps: Troubleshooting Outlook search issues
If this case still persists, please contact New Outlook for Windows Support Team via clicking Help>Contact Supportor Contact support and provide feedback within the new Outlook for Windows. The support team over there has higher permission than us, they can remotely help you and collect logs at your convenience. They can also involve more resources to investigate the issue from backend side. This would be the most efficient way in handling this case for you.
Your understanding and patience will be appreciated.
Thank you!