Outlook uses the Windows Search index to find emails quickly. If the index is incomplete, outdated, or pointing at the wrong locations, searches will return nothing — even for emails you can clearly see in your inbox.

Check Whether Windows Search Is Running

Press Win + R, type services.msc, and press Enter. Find Windows Search in the list. Its status should be Running. If it is stopped, right-click it and choose Start. Set the Startup type to Automatic so it starts with Windows in future.

Rebuild the Search Index

This is the most reliable fix.

  1. Open Control Panel and search for Indexing Options.
  2. Click Advanced.
  3. Under the Troubleshooting section, click Rebuild.
  4. Click OK to confirm. The rebuild can take anywhere from 20 minutes to a few hours depending on how much email you have. Outlook search will gradually improve as indexing progresses.

Make Sure Outlook Is Included in the Index

In the same Indexing Options window, click Modify and confirm that Microsoft Outlook (or your email data file location) is checked. If it is not listed, add it.

Repair Your Outlook Data File

A corrupted PST or OST file can also prevent search from working. Close Outlook, then run the inbox repair tool:

  1. Navigate to C:\Program Files\Microsoft Office oot\Office16\ (the exact path may vary by Office version).
  2. Run SCANPST.EXE.
  3. Browse to your data file, click Start, and follow the repair steps.

Outlook on the Web (Outlook.com)

If you use Outlook through a browser, search is handled server-side and does not depend on the Windows index. If search is not working there, try clearing your browser cache or using a different browser. If the problem persists, it may be a temporary Microsoft service issue.

Need more help? Ask us and mention which version of Outlook you are using.