Outlook Search Not Working or Returning No Results? Rebuild the Index

You type a sender or keyword into Outlook’s search box and get nothing — or only old mail, missing everything recent.

Why: Outlook (classic) relies on the Windows Search index. If indexing hasn’t finished, the service is stopped, or the catalog is corrupt, searches come back partial or empty even though the mail is right there in your mailbox.

Fix 1: Check the indexing status first

Don’t rebuild anything until you know whether indexing is simply still running.

1. In Outlook, click the Search box so the Search tab appears on the ribbon.
2. Search → Search Tools → Indexing Status.
3. If it says “Outlook has finished indexing all your items. 0 items remaining to be indexed,” the index is fine — skip to Fix 3. If thousands of items remain, leave the PC on and let it finish (a large mailbox can take hours).

Fix 2: Confirm the Windows Search service is running

If indexing never progresses, the service may be stopped.

1. Win + R → services.msc → Enter.
2. Find Windows Search, double-click it.
3. Set Startup type to Automatic (Delayed Start), click Start if it’s stopped, then OK.

Fix 3: Confirm Outlook is on the index list

1. Close Outlook.
2. Control Panel (icon view) → Indexing Options.
3. Under Included Locations, confirm Microsoft Outlook is ticked. If not, click Modify, tick it, and OK.

Fix 4: Rebuild the index

This is the actual fix when the catalog is corrupt or stale.

1. Close Outlook.
2. Control Panel → Indexing Options → Advanced.
3. On the Index Settings tab, under Troubleshooting, click Rebuild, then OK on the warning.
4. The index is deleted and rebuilt from zero — this can take a few hours to a day or two on a big mailbox. Search will return partial results until it finishes, so leave the machine on.

FAQ

Why did search break right after a Windows update? A few updates have knocked out Outlook indexing; rebuilding the index (Fix 4) restores it, and installing the latest Office and Windows updates prevents a repeat.

Do I have to rebuild every time it’s slow? No. Rebuilding is a last resort — check Indexing Status (Fix 1) first, because a search that “fails” is often just an index that hasn’t finished yet.

Sources: Microsoft Support — Troubleshooting Outlook search issues