Troubleshoot Windows Search performance

This article provides guidelines for troubleshooting poor Windows Search performance.

Applies to:   Windows 10 – all editions
Original KB number:   4558579

Summary

This article discusses common performance issues that affect Windows Search and Search indexing.

If you observe general poor performance when you search or when Windows builds a search index, go to Tune the Indexer performance.

If you observe specific error messages, go to Troubleshoot Search errors.

More information

Tune the Indexer performance

The primary factors that affect indexing performance are the number of items indexed and the overall size of the index. These factors are related but separate.

Number of items indexed

On a typical user's computer, the Indexer indexes fewer than 30,000 items. On a power user's computer, the Indexer might index up to 300,000 items. If the Indexer indexes more than 400,000 items, you may begin to see performance issues. For more information, go to Size of the index database.

The Indexer can index up to 1 million items. If the Indexer tries to index beyond that limit, it may fail or cause resource problems on the computer (such as high usage of CPU, memory, or disk space).

To check the number of indexed items, select Settings > Search > Searching Windows, and then check the value of Indexed items.

Size of the index database

As the number of indexed items grows beyond 400,000, the index database grows considerably regardless of the size of those items. The size of the items also affects database size. A database that contains either a few large files or a large number of smaller files can affect performance. Both factors together can compound the problem. The Indexer tries to compress the index data. However, this approach becomes less effective as the index database grows.

By default, Windows.edb is located in the C:\ProgramData\Microsoft\Search\Data\Applications\Windows folder. To check the size of the file, follow these steps:

1. Right-click Windows.edb, and select Properties.

2. Check the Size on disk value. This property reflects the actual disk space that the database uses.

   

Tuning methods

You can use any of several approaches to improve the performance of Search and the Search Indexer.

Let the Indexer run for up to 24 hours to rebuild the index database.

Exclude folders

You can use this approach to reduce the number of items that are indexed and to reduce the size of the index database. To exclude whole folders from the index, select Settings > Search > Searching Windows > Add an excluded folder. And then select a folder to exclude.

For a more granular method to include or exclude items, open Searching Windows, and select Advanced Search Indexer Settings. In Indexing Options, select Modify, and then select or deselect locations to index.

Change how the Indexer treats specific file types

To control how the indexer treats specific file types, open Indexing Options, and select Advanced > File Types. You can change how the Indexer treats specific file types (identified by file extension) or add and configure new file types.

Defragment the index database

You can use this approach to reclaim empty space within the index database. Open an administrative Command Prompt window, and then run the following commands in the given order:

Sc config wsearch start=disabled
Net stop wsearch
EsentUtl.exe /d %AllUsersProfile%\Microsoft\Search\Data\Applications\Windows\Windows.edb
Sc config wsearch start=delayed-auto
Net start wsearch

For more information about how to defragment the index database, see the following Knowledge Base article:

2952967 Windows.edb larger than expected when a PST file is indexed in Windows

Change Outlook settings

To help reduce the content of an Outlook mailbox, you can change the synchronization window to a shorter time interval than the default interval of one year. For more information, see the following article:

3115009 Update allows administrators to set additional default mail and calendar synchronization windows for new Exchange accounts in Outlook 2016

Troubleshoot Search errors

If the Indexer successfully builds the index database, you see the message Indexing complete on the Windows Search settings page and in Indexing Options.

If a different message appears, see the following table for more information about the message and how to respond.