Why is MsSearch.exe consuming so much memory and CPU?

MsSearch.exe builds and maintains full-text indexes. High resource usage typically occurs during initial index population, after large data imports, or during index merges. This is normal behavior during heavy indexing activity and should subside once the index is current.

Can I safely disable MsSearch.exe?

Only if you do not need full-text search. Disabling it will break full-text queries in SQL Server, content indexing in Exchange, and search functionality in SharePoint. If you only need to reduce its impact temporarily, you can pause or schedule indexing during off-peak hours.

What is the difference between MsSearch.exe and Windows Search (SearchIndexer.exe)?

MsSearch.exe is the Microsoft Search service used by SQL Server Full-Text Search, Exchange Server, and SharePoint. SearchIndexer.exe (Windows Search) is the desktop search indexer built into Windows for indexing files, emails, and other content on local drives. They are separate services.

MsSearch.exe: Microsoft Search Service Explained

MsSearch.exe is the executable for the Microsoft Search service, a component used by SQL Server, Exchange Server, and SharePoint Server to build and maintain full-text indexes. This process enables fast search queries across large datasets by creating searchable indexes of text content. While it is essential for search functionality, it can sometimes consume significant CPU and memory resources.

What MsSearch.exe Does

The Microsoft Search service provides full-text indexing and search capabilities for several Microsoft server products:

SQL Server Full-Text Search: Indexes text columns in SQL Server databases so that applications can perform linguistic searches, proximity searches, and weighted term queries.
Exchange Server: Indexes mailbox content (emails, attachments, calendar items) to power Exchange search and eDiscovery features.
SharePoint Server: Indexes documents, list items, and other content across SharePoint sites to power the search experience.

The process works by crawling content, breaking it into tokens, and storing those tokens in an inverted index structure. When a search query is executed, the service looks up matching tokens in the index rather than scanning every document, which is dramatically faster.

Where MsSearch.exe Runs

The executable is typically located in:

SQL Server: C:\Program Files\Microsoft SQL Server\MSSQL{version}\MSSQL\Binn\
Exchange Server: Within the Exchange installation directory under the search-related component folders.
SharePoint: As part of the SharePoint search service application.

The associated Windows service names vary by product:

Product	Service Name	Service Display Name
SQL Server	`msftesql` or `MSSQLFDLauncher`	SQL Full-Text Filter Daemon Launcher
Exchange	`MSExchangeSearch`	Microsoft Exchange Search
SharePoint	`OSearch{version}`	SharePoint Search

High CPU and Memory Usage

MsSearch.exe is known for consuming substantial resources during certain operations. This is generally expected behavior, but it can impact server performance.

When High Usage Is Normal

Initial index population: When full-text indexing is first enabled or after rebuilding an index, MsSearch.exe must crawl all content. This is CPU and I/O intensive.
Large data changes: Bulk imports, mailbox migrations, or large document uploads trigger significant indexing activity.
Index merges: The service periodically merges smaller index fragments into larger ones, which requires temporary spikes in resource usage.
Crawl schedules: SharePoint incremental and full crawls drive indexing activity.

When High Usage Indicates a Problem

Continuous high CPU for hours or days outside of bulk operations may indicate a corrupt index or configuration issue.
Memory consumption growing unbounded can suggest a memory leak in an older version of the service.
Repeated indexing of the same content points to a crawl loop or data source configuration error.

Troubleshooting MsSearch.exe Issues

Check the Indexing Status

For SQL Server, query the indexing status:

-- Check full-text index population status
SELECT OBJECTPROPERTYEX(OBJECT_ID('YourTable'), 'TableFullTextPopulateStatus') AS PopulateStatus;

-- 0 = Idle, 1 = Full population in progress
-- 2 = Manual population in progress, 4 = Throttled
-- 5 = Change tracking auto population

Restart the Search Service

If the service is misbehaving, you can restart it:

# For SQL Server Full-Text
Restart-Service MSSQLFDLauncher

# For Exchange Search
Restart-Service MSExchangeSearch

# For Windows Search (desktop)
Restart-Service WSearch

Rebuild the Full-Text Index (SQL Server)

If the index is corrupt, rebuild it:

ALTER FULLTEXT CATALOG YourCatalog REBUILD;

Or for a specific table:

ALTER FULLTEXT INDEX ON YourTable START FULL POPULATION;

Throttle Indexing Activity

For SQL Server, you can configure the search service to use fewer resources:

-- Set maximum number of threads for full-text indexing
EXEC sp_configure 'max full-text crawl range count', 4;
RECONFIGURE;

For Exchange, you can throttle search indexing through Exchange Management Shell or by adjusting the search service configuration.

Check Event Logs

Review the following event logs for errors related to indexing:

Application Log: Look for events from source MSSEARCH or MSSearch.
Exchange-specific logs: Check MSExchange Search Indexer events.
SharePoint ULS logs: Search for crawl and indexing errors.

Disabling MsSearch.exe

If you do not use full-text search, you can disable the service to reclaim resources.

Disable SQL Server Full-Text Search

# Stop and disable the Full-Text Filter Daemon Launcher
Stop-Service MSSQLFDLauncher
Set-Service MSSQLFDLauncher -StartupType Disabled

Alternatively, if full-text search was installed as a SQL Server feature, you can remove it through the SQL Server installer by modifying the installation and unchecking Full-Text and Semantic Extractions for Search.

Disable Exchange Search

Disabling Exchange Search is generally not recommended because it affects mailbox search, compliance features, and eDiscovery. If you must disable it temporarily for troubleshooting:

Stop-Service MSExchangeSearch
Set-Service MSExchangeSearch -StartupType Disabled

Remember to re-enable it after troubleshooting.

MsSearch.exe vs. Windows Search (SearchIndexer.exe)

These are two distinct services that are often confused:

Feature	MsSearch.exe	SearchIndexer.exe
Purpose	Server-side full-text indexing	Desktop file and content indexing
Used by	SQL Server, Exchange, SharePoint	Windows Explorer, Outlook desktop
Service name	Varies by product	WSearch
Scope	Database and server content	Local files, email, and metadata

On a server running both SQL Server and Windows, both processes may be active simultaneously.

Best Practices

Schedule heavy indexing during off-peak hours to minimize impact on production workloads.
Monitor disk space for the index files, as full-text indexes can grow large.
Keep the server products patched to benefit from performance improvements and bug fixes in the search components.
Size memory appropriately for servers running full-text indexing alongside other workloads.
Use Resource Governor in SQL Server to limit CPU and memory consumption by the full-text indexing process.

Summary

MsSearch.exe is the Microsoft Search service executable that provides full-text indexing for SQL Server, Exchange Server, and SharePoint. High CPU and memory usage during indexing operations is expected behavior, particularly during initial index builds or after large data changes. If resource consumption is problematic, you can throttle indexing, restart the service, rebuild corrupt indexes, or disable the service entirely if full-text search is not needed.