SearchIndexer.exe

Windows ProcessMicrosoft Corporation

Also called searchindexer, windows search indexer, microsoft windows search indexer

WindowsSystem Component

Windows Search Indexer. It crawls files so Start and File Explorer can answer without walking the whole disk each time.

What you need to know

This writes the search index. SearchHost.exe is the search box you type into.

SearchIndexer.exe is the WSearch worker. High disk after an upgrade or a new folder is a rebuild. SearchHost.exe is the UI. They are not the same process.

Safe?: Yes. It builds the index
High disk after a copy?: Often a crawl
Same as SearchHost?: No. SearchHost is the box

Feex says

If the indexer is loud and I just dumped 200 GB onto the PC, I would let it crawl. Disabling WSearch makes every later search walk the disk again.

What is SearchIndexer.exe?

SearchIndexer.exe is the Windows Search Indexer. It is the process you should expect when WSearch is Automatic. SearchHost.exe draws the search home.

What does it do?

It enumerates included folders, parses properties, and writes the index catalog. Outlook cached mail can also be in scope on some PCs.

Why is it running?

Files changed, a location was added, or Windows is rebuilding after a feature update. Idle indexer should settle. Days of 100 percent disk on an SSD needs Indexing Options.

Is it safe?

Usually safe

The legitimate indexer is in System32. A SearchIndexer.exe in a "speed up search" zip is not WSearch.

A legitimate copy normally runs from:

C:\Windows\System32\SearchIndexer.exe

Expected publisher: Microsoft Corporation
Service: WSearch
UI process: SearchHost.exe

Can I end it?

Search gets slower

Ending the indexer pauses the crawl until WSearch starts it again. It does not permanently shrink the index. Use Indexing Options to drop a huge folder.

Can I remove it?

Do not delete SearchIndexer.exe. Disable WSearch only if you accept unindexed search. That is a service decision.

Should it start with Windows?

WSearch starts the indexer. It is not Discord in Startup Apps.

Normal resource behavior

These are contextual labels, not universal averages.

CPU: Rises while parsing new files
Memory: Moderate
Disk: The usual complaint, especially on HDD
Network: If a location is a UNC path

File information

SearchIndexer.exe file information
Executable name	SearchIndexer.exe
Common legitimate path	C:\Windows\System32\SearchIndexer.exe
Publisher	Microsoft Corporation
Signature expectation	Signed by Microsoft Windows

Common problems

Rebuild after a feature update

Indexing Options shows status. A rebuild is hours on a large HDD. That is expected work.

Cloud folders

OneDrive files on-demand can make the indexer wake often. Exclude the library as a test before you disable WSearch.

Troubleshooting

Diagnose before you change anything destructive.

Indexing Options first

See included locations and pause. Do not delete the catalog folder as a first step.

Rebuild only after a broken index

A rebuild is a real job. It is not a weekly tune-up.

Technical details

SearchIndexer.exe technical details
Image name	SearchIndexer.exe
Service	WSearch

Sources and verification

Reviewed by Feex editorial. Last verified August 2026 Status: Feex Reviewed. How we research.

Microsoft Learn: Windows Search · Indexer and WSearch
Microsoft Support: indexing options · Rebuild and locations
Foxhole process map · First-party samples on Windows PCs. Not a lab benchmark.

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