Outlook Keeps Asking to Rebuild Search Index? Complete Fix (2025)

Outlook Keeps Asking to Rebuild Search Index? Here’s the 2025 Fix

Is your Outlook stuck in an endless loop where it keeps telling you to rebuild the search index, but even after doing it, the message comes back again and again?

You type something in Outlook search, it doesn’t show all emails, and Outlook shows:

• “Search results may be incomplete because items are still being indexed.”
• Or a yellow bar suggesting you to rebuild the index.

If this sounds familiar, you’re not alone. After recent Windows and Microsoft 365 updates, many users on Windows 10 and Windows 11 are facing this issue where Outlook:

• Keeps showing index rebuild messages
• Takes too long to index
• Repeats the same message even after rebuilding

In this guide, we’ll walk you through the real reasons behind this problem and the step-by-step fixes you can follow to finally stop Outlook from asking to rebuild the search index.

Common Symptoms of the Outlook Indexing Loop

You are likely facing this issue if:

• Outlook search is slow or missing recent emails
• Outlook keeps showing “Indexing in progress” for hours
• You click Rebuild Index, it finishes, and the message still returns
• Search results show only old mails, not newer ones
• Your CPU usage increases while indexing, but nothing improves

The problem is usually a combination of Windows Search service, Outlook data files (OST/PST), and sometimes add-ins or corrupted profiles.

Why Outlook Keeps Asking to Rebuild the Search Index

Some of the most common reasons include:

• Windows Search service not running properly
• Corrupted search index database on Windows
• Large or corrupted OST/PST files used by Outlook
• Problematic Outlook add-ins interfering with search
• Multiple Outlook profiles or old profiles still in the system
• Recent Windows / Office updates changing how indexing behaves

Let’s go through the fixes one by one. Start from the top and go in order – in many cases, the issue is solved before you reach the advanced steps.

Fix 1 – Make Sure Windows Search Service Is Running

Outlook search relies on the Windows Search service. If that service is disabled, stuck, or crashing, Outlook will keep asking to rebuild the index.

1. Press Windows + R, type services.msc and press Enter.
2. In the list, find Windows Search.
3. Right-click it and click Properties.
4. Set Startup type to Automatic.
5. If the service is stopped, click Start.
6. Click OK and close the window.

Restart Outlook and test the search again. If the message still appears, move to the next step.

Fix 2 – Rebuild the Index the Correct Way

If you’ve rebuilt the index from error pop-ups only, do a clean rebuild from the Indexing Options panel.

1. Close Outlook completely.
2. Press Windows + S and search for Indexing Options, then open it.
3. Click on Modify and confirm that Microsoft Outlook is checked.
4. Click Advanced (you might be asked for admin permission).
5. Under the Index Settings tab, click Rebuild.
6. Click OK to confirm.

Windows will now completely rebuild the search index. Depending on mailbox size and PC speed, this can take from a few minutes to a couple of hours. You can continue to use Outlook during this process.

Fix 3 – Check Outlook’s Indexing Status from Inside Outlook

After rebuilding, confirm if Outlook is still indexing too many items or if it’s stuck.

1. In Outlook, go to the Search box.
2. Click inside the search bar, then look for Search Tools → Indexing Status.
3. Outlook will show how many items are left to index.

If you constantly see a high number of items, or it never reaches zero, the problem may be with your data files (OST/PST).

Fix 4 – Repair Your Outlook Data File (OST/PST)

A corrupted OST/PST file can cause Outlook search and index issues. You can repair these files using the built-in Microsoft tool.

Step 1 – Locate the OST/PST file:

1. In Outlook, go to File → Account Settings → Account Settings.
2. Go to the Data Files tab.
3. Select your main mailbox and click Open File Location.

Step 2 – Run the Inbox Repair Tool (scanpst.exe):

You can usually find scanpst.exe in one of these paths:

• C:\Program Files\Microsoft Office\root\Office16
• C:\Program Files (x86)\Microsoft Office\root\Office16

1. Close Outlook.
2. Run scanpst.exe.
3. Browse to the OST/PST file and click Start.
4. If errors are found, choose Repair.

Once done, reopen Outlook and let it sync and index again.

Fix 5 – Disable Problematic Outlook Add-ins

Some third-party add-ins can interfere with Outlook’s search and indexing.

1. In Outlook, go to File → Options.
2. Click on Add-ins.
3. At the bottom, next to Manage, select COM Add-ins and click Go.
4. Uncheck non-Microsoft add-ins one by one (or all at once for testing).
5. Click OK and restart Outlook.

Test the search again. If the problem is gone, re-enable add-ins one by one to identify which one was causing it.

Fix 6 – Create a Fresh Outlook Profile

If your Outlook profile has been around for years, it may carry hidden issues that affect search and indexing.

1. Close Outlook.
2. Press Windows + R, type control and press Enter.
3. In Control Panel, search for Mail and open Mail (Microsoft Outlook).
4. Click on Show Profiles.
5. Click Add, create a new profile, and add your email account again.
6. Select Always use this profile and choose the new profile.

Start Outlook with the new profile and allow time for the mailbox to sync. Then check if the search index issue is resolved.

Fix 7 – Repair Microsoft 365 / Office Installation

If the problem started right after an Office update or installation, repairing Microsoft 365 might help.

1. Press Windows + X and click Apps & Features (or Installed Apps).
2. Find Microsoft 365 or Office 365 in the list.
3. Click on it and choose Modify.
4. Select Quick Repair first and run it.
5. If the issue remains, repeat and choose Online Repair (this takes longer and requires internet).

After the repair, restart your PC and test Outlook search again.

Advanced Option – Reset Windows Search Completely

Warning: This is for advanced users or with expert guidance.

If none of the above worked and Outlook still keeps asking you to rebuild the search index, you may consider resetting Windows Search completely using PowerShell or specific fix-it scripts from Microsoft’s official support.

Because this can affect other search features in Windows, many users prefer to get remote help instead of trying it alone.

Outlook Index Rebuild Taking Too Long? Here’s What to Check

• Ensure your PC is not going to sleep during indexing
• Keep Outlook open and connected to the internet
• Close heavy apps that use a lot of CPU or disk
• Check that your mailbox isn’t extremely huge (40GB+ OST can be very slow)

For very large mailboxes, sometimes the better long-term solution is to archive old emails and keep your active mailbox smaller.

How to Prevent This Issue in the Future

• Avoid abrupt shutdowns while Outlook is running
• Keep Windows and Office updated, but restart after big updates
• Don’t force close Outlook frequently from Task Manager
• Archive or auto-archive very old emails
• Check your OST/PST health periodically, especially on older systems

Still Stuck? Get Help from a Live Outlook & Microsoft 365 Expert

If you have tried all these steps and Outlook still keeps asking to rebuild the search index, or search is incomplete even after hours of indexing, the issue may be deeper – for example:

• Damaged user profile
• Hidden registry-level issues
• Conflicts with security software
• Multiple data files or accounts misconfigured

In those cases, it’s faster and safer to let an experienced technician diagnose the problem directly on your system.

You can share your screen, let an expert check your Outlook, Windows Search, and data files, and get everything working again without guessing and without losing your emails.

If you are not comfortable doing advanced fixes on your own, you can reach out for live support and get step-by-step guided help.

FAQ – Outlook Search Index Issues (2025)

1. How long should Outlook take to rebuild the search index?

It depends on your mailbox size and PC speed. For small mailboxes, it may take 10–30 minutes. For large or multiple mailboxes, it can take a few hours. If nothing improves after many hours or days, there is likely a deeper issue.

2. Is it safe to rebuild the search index?

Yes. Rebuilding the Windows search index does not delete your emails or data. It only recreates the index that Windows and Outlook use to search quickly.

3. Will repairing my OST/PST delete any emails?

No, running scanpst.exe is designed to fix structural issues in the data file. However, it’s always a good idea to take a backup of the file before repairing, especially if it is very large.

4. Why does Outlook search work on one PC but not another?

Outlook search depends on Windows Search, local index settings, and data files on each computer. If one system has corrupted index data or a damaged OST/PST, search problems may appear only on that device.

5. Does creating a new Outlook profile help?

Yes, in many cases a fresh profile with a new OST file can fix persistent indexing and search issues, especially if the old profile has been carried over through multiple upgrades and configurations.