Outlook Search Not Working — What Causes It & How to Fix It

What Does This Error Mean?

When Outlook search stops working, it returns no results, partial results, or old results that should have been updated. This is almost always caused by a corrupted or outdated search index. Outlook relies on Windows Search to index your emails. Rebuilding the index usually fixes the problem within an hour.

Affected Models

Microsoft Outlook 2016
Microsoft Outlook 2019
Microsoft Outlook 2021
Microsoft 365 Outlook
Outlook for Windows

Common Causes

The Windows Search index for Outlook has become corrupted and needs to be rebuilt
The Outlook data file (PST or OST) is not included in the Windows Search indexing locations
Windows Search service has stopped running in the background
A recent Windows or Office update changed the search indexing settings
The Outlook mailbox is very large and the index has not finished building yet

How to Fix It

First, confirm the Windows Search service is running. Press Windows + R, type services.msc, and press Enter. Scroll to 'Windows Search'. Its status should say 'Running'. If it is stopped, right-click it and select Start.

If Windows Search is stopped, Outlook cannot index emails and search will return nothing.
Rebuild the Outlook search index. In Outlook, go to File > Options > Search > Indexing Options. Click 'Advanced', then click 'Rebuild'. Click OK when warned it may take a while.

Rebuilding can take 20 minutes to several hours depending on how many emails you have. Search may return incomplete results until the rebuild is done.
Make sure your Outlook data file is included in the index. In Indexing Options (from Step 2), click 'Modify'. Expand the list and make sure your Outlook inbox is checked.

If the Outlook data file is not in the indexed locations, search will never find emails no matter how many times you rebuild.
If search still fails, try repairing the Office installation. Go to Windows Settings > Apps > Microsoft Office, click Modify, and run Quick Repair.

Quick Repair fixes corrupted Outlook files without reinstalling Office. Online Repair is more thorough but requires an internet connection.
Check if the issue is with a specific folder. Outlook search sometimes fails in Archived folders or large shared mailboxes. Try searching in the Inbox only first to confirm the index is working.

Use the dropdown in the Outlook search bar to limit search to 'Current Folder' or 'All Mailboxes'.

When to Call a Professional

Outlook search issues are a software configuration problem. You do not need a technician — all fixes are done through Outlook settings and Windows settings. If rebuilding the index does not resolve it, a repair of the Office installation will.

Frequently Asked Questions

Why did Outlook search suddenly stop working after a Windows update?

Windows updates sometimes reset or disrupt the Search indexing service. After a major update, the Windows Search index may need to be rebuilt. Check that the Windows Search service is running and rebuild the Outlook index using the steps above.

Outlook search finds old emails but not new ones. What's wrong?

The index is out of date. This happens when the indexing process is running slowly or has stalled. Check the Indexing Options dialog in Outlook — it will show how many items are still waiting to be indexed. If the number is large and not decreasing, try rebuilding the index.

Is there a faster way to search Outlook without relying on the index?

Yes. In Outlook, you can use Instant Search with specific fields. For example: from:[email protected] or subject:invoice will search specific fields. These searches are faster because they target specific columns in the mailbox database. However, full-text body searches (searching email content) require the index.