Rebuild Outlook Search Index to Fix Missing Emails

If Outlook’s search stops showing results or older emails have vanished from the search pane, your search index may be corrupted. Outlook depends on the Windows Search service to quickly locate emails, attachments, and contacts. When that index becomes outdated or damaged, Outlook fails to display the correct results. This guide walks you through how to rebuild and optimize the Outlook search index step-by-step for Outlook 2016 through 2025.

Symptoms of a Broken Outlook Search Index

• Outlook shows No results found even when the message exists.
• Recent emails don’t appear in search results.
• Only partial results load, or search takes too long.
• Outlook freezes while indexing messages.

1. Check the Outlook Indexing Status

Before rebuilding, check whether Outlook is still indexing or stuck.

1. Open Outlook → click Search box → select Search Tools → Indexing Status.
2. If you see “Outlook has finished indexing all items,” no rebuild is needed.
3. If it lists thousands of remaining items, the index may be corrupt or incomplete.

2. Rebuild the Outlook Search Index

Follow these steps to recreate the search index and fix missing emails:

1. Close Outlook.
2. Open Control Panel → Indexing Options.
3. Click Advanced.
4. Under the Index Settings tab, click Rebuild.
5. Confirm by clicking OK.

Rebuilding may take several hours depending on the size of your mailbox, but Outlook will gradually repopulate results as indexing progresses.

3. Verify Outlook is Included in the Index

Sometimes Outlook folders are excluded accidentally.

1. In the same Indexing Options window, click Modify.
2. Make sure Microsoft Outlook is checked under indexed locations.
3. Click OK to save changes and restart Outlook.

4. Repair Windows Search Service

If rebuilding didn’t help, the underlying Windows Search service might be disabled or malfunctioning.

1. Press Windows + R, type services.msc, and hit Enter.
2. Scroll to Windows Search.
3. Right-click → choose Properties.
4. Set Startup type to Automatic (Delayed Start) and click Start.

5. Optimize Your Outlook Data Files

A large or corrupted OST/PST file can slow indexing or cause Outlook search to stop responding.

1. Close Outlook and run SCANPST.EXE to repair your data file.
2. Compact the file by going to File → Account Settings → Data Files → Settings → Compact Now.
3. Restart Outlook and let indexing resume.

6. Update and Re-sync Outlook

Always install the latest Office and Windows updates. Old builds often contain indexing bugs. If you use Exchange or Microsoft 365, a full resync may also help.

1. Go to File → Office Account → Update Options → Update Now.
2. Ensure your internet connection is stable during synchronization.

7. Use Advanced Search Filters

If results still seem incomplete, use targeted search operators:

from:john subject:report hasattachments:yes received:this week

This narrows results and helps verify whether indexing or filtering is the issue.

Related Articles

• Outlook Not Opening or Crashing on Startup
• Email Setup and Configuration
• Fix Outlook and Office 365 Sync Issues

Conclusion

Rebuilding the Outlook search index resolves most missing email and slow search issues. After rebuilding, Outlook continues indexing in the background, so results improve over time. Keep Outlook and Windows up-to-date and regularly compact data files for best performance.