Is Outlook not searching emails? A simple restart or configuration in the settings often resolves the issue. If it doesn’t, you may need to rebuild your search index.

Outlook is a powerful tool many offices rely on for its versatile features, including Mail, Task Manager, and Calendar. One of its most powerful tools is the search box, which lets you quickly find messages, contacts, tasks, and calendar items using keywords. However, when this feature malfunctions, it can disrupt productivity.

Fortunately, rebuilding the search index is straightforward. Here’s a quick guide on how to fix indexing issues in Outlook.

✶ Missing the search bar in Outlook? Here’s how to add it back

Why Rebuilding Your Search Index Is Important

There are two key reasons to rebuild your search index:

1. Institutional Memory

Corporate and consumer emails were projected to reach 347.3 billion per day in 2023. With the average person sending and receiving 121 business emails daily, organizations collect vast amounts of information annually.

Corporate emails often store critical data such as vendor communications, price quotes, and license agreements. This “institutional memory” keeps teams and processes running efficiently. Rebuilding your search index ensures this knowledge remains accessible, prevents data silos, and supports effective knowledge management.

2. Search Optimization

Businesses typically use two types of searches: federated search and enterprise search.

• Federated search pulls results from both internal and external sources.
• Enterprise search retrieves results from a single source.

Rebuilding indexes optimizes query times, eliminates fragmentation, reclaims storage space, and organizes index rows. Additionally, secure enterprise search safeguards sensitive data, ensuring it remains accessible only to authorized users.

✶ Key features your enterprise search tool should have

When to Rebuild Your Search Index

Rebuild the search index if you encounter any of the following issues:

• Outlook search returns 0 results
• Outlook search does not display all results
• Outlook search fails to find old or recent emails
• Outlook search can’t find any matches
• The search tab is grayed out (Outlook 2016)

These issues often occur due to a corrupt index or incomplete indexing. Rebuilding the search catalog re-indexes your data files and typically resolves the problem.

During rebuilding, searches may not work, so be patient. Once complete, restart your computer and reopen Outlook. Your searches should now work as expected.

✶ Want to optimize your search? Federated search can help

How Long Does Rebuilding the Index Take?

Rebuilding the index duration depends on the volume of items and your system’s processing power. It can take anywhere from 12 to 24 hours.

To speed up the process:

• Rebuild the index when you’re not actively using your computer.
• Close other applications to improve indexing speed.

To check progress, open the Indexing Options box and view the status at the top. Once complete, test searches for improvements in speed and functionality.

Steps to Rebuild the Search Index on Microsoft Outlook 365

Rebuild Index for Windows

Solution 1: Using Programs and Features

1. Open the Control Panel by typing “control” in the Windows search box and selecting it.
2. Go to Programs > Programs & Features.
3. Scroll to Microsoft 365 and select Change.
4. Choose Quick Repair or Online Repair (Quick Repair works offline).
5. Restart your computer when the repair completes.

Solution 2: Using the Index Repair Menu in Outlook

1. Open Outlook and go to File > Options > Search.
2. Click Indexing Options, then Advanced. Administrator access may be required.
3. Select Rebuild and click OK.
4. Restart your computer after rebuilding completes.

Rebuild Index on Mac

1. Open System Preferences from the Apple menu.
2. Go to Spotlight > Privacy.
3. Add your Home folder to the list of non-indexed folders by clicking the (+) icon.
4. If prompted, confirm by selecting OK.
5. After a minute, remove the folder by clicking the (–) icon.
6. Close Spotlight preferences.

Rebuilding may take time, especially with a high volume of contacts and emails. Once finished, test the search functionality.

Rebuilding the Exchange Search Index

If you use an Exchange account, follow these methods:

Option 1
Run this command in Exchange Server 2019:
Start-MailboxAssistant -Identity <mailbox> -AssistName BigFunnelRetryFeederTimeBasedAssistant

Option 2
Use Microsoft’s commands:

1. Create a setting override:
   New-SettingOverride -Name "Big Funnel Permanent Retry" ...
2. Update configurations:
   Get-ExchangeDiagnosticInfo ... -Argument Refresh

Option 3
Move the mailbox to another database:
New-MoveRequest <usermailbox> -TargetDatabase <databasename>

What If Rebuilding Doesn’t Work?

If rebuilding doesn’t resolve the issue, try these steps:

1. Check if Outlook is listed in Indexing Options under File > Options > Search.
2. Ensure the .msg file extension is selected under Advanced > Files.
3. Verify that Outlook is up-to-date via File > Office Account > Update Options > Update Now.

Optimize Your Search With Unleash

Rebuilding the Outlook search index is a quick solution to many issues. However, investing in a powerful enterprise search tool like Unleash ensures your data remains secure, easily accessible, and optimized for productivity.

✶ Ready to transform your search experience? Try Unleash today!

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