Troubleshooting “Search Index is Corrupted” in SharePoint

When SharePoint’s search index is corrupted, search queries may fail, return incomplete results, or cause performance issues. Index corruption can occur due to abrupt server shutdowns, insufficient storage, software bugs, or database inconsistencies. This guide provides a detailed step-by-step approach to diagnose and fix the issue.

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Step 1: Confirm Search Index Corruption

Before troubleshooting, verify if the search index is truly corrupted.

1.1: Check for Common Search Errors

1. Perform a test search on your SharePoint site.
2. If you encounter errors like:
   • “Search index is corrupted”
   • “Search encountered an error and cannot display results”
   • “Search service is unavailable”
   • “Unexpected query failure”
3. If results are incomplete or missing, search index corruption is likely.

1.2: Check ULS Logs for Index Errors

The Unified Logging System (ULS) logs can provide more details.

1. Open SharePoint Management Shell as an Administrator.
2. Run the following command to filter search-related logs: Get-SPLogEvent | Where-Object { $_.Category -eq "Search Indexing" } | Select-Object -First 20
3. Look for error messages like:
   • “Corrupt index detected, reset required.”
   • “Search component failure: Index out of sync.”
   • “Index files missing or inaccessible.”

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Step 2: Restart the Search Service

A simple restart may resolve minor corruption issues.

2.1: Restart Search Service from Central Administration

1. Open Central Administration.
2. Go to Manage Services on Server.
3. Locate SharePoint Server Search.
4. Click Restart.

2.2: Restart Search Service Using PowerShell

Run the following commands in PowerShell:

Restart-Service -Name OSearch15 -Force
Restart-Service -Name SPSearchHostController -Force

After restarting, check if search is working.

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Step 3: Reset the Search Index

If restarting does not fix the issue, reset the search index.

3.1: Reset Search Index via Central Administration

1. Open Central Administration.
2. Navigate to Manage Service Applications.
3. Select Search Service Application.
4. Click Index Reset (⚠ This will delete the entire index!).
5. Click Reset Now.

3.2: Reset Search Index Using PowerShell

If you prefer PowerShell, use:

$ssa = Get-SPEnterpriseSearchServiceApplication
$ssa.ResetSearchIndex()

Once the index is reset, a full crawl is required.

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Step 4: Perform a Full Crawl

A full crawl rebuilds the index with fresh data.

4.1: Start a Full Crawl from Central Administration

1. Open Central Administration.
2. Navigate to Search Service Application > Content Sources.
3. Select SharePoint Sites.
4. Click Start Full Crawl.

4.2: Start a Full Crawl Using PowerShell

$ssa = Get-SPEnterpriseSearchServiceApplication
Start-SPEnterpriseSearchFullCrawl -SearchApplication $ssa

Monitor the crawl progress in Crawl Logs.

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Step 5: Verify Crawl Logs for Errors

If the full crawl fails, investigate the Crawl Logs.

1. Open Central Administration.
2. Navigate to Search Service Application > Crawl Logs.
3. Check for errors like:
   • Access Denied
   • Content Source Unreachable
   • Insufficient Permissions
   • Time-out Issues

If errors appear, resolve them before proceeding.

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Step 6: Verify Search Component Health

A corrupted Search Component can cause index corruption.

1. Open Central Administration.
2. Go to Search Service Application.
3. Click Search Administration > Search Topology.
4. Check if components like Index Component, Query Processing Component, and Crawl Component are running.

If any component is in a failed state, restart them:

Restart-Service -Name SPSearchHostController -Force
Restart-Service -Name OSearch15 -Force

If restarting fails, consider rebuilding the Search Topology (explained later).

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Step 7: Ensure Sufficient Disk Space

Search index corruption can happen due to low disk space.

1. Open File Explorer on the SharePoint server.
2. Check the drive hosting the search index (default: C:\Program Files\Microsoft Office Servers\15.0\Data).
3. Ensure at least 20% free disk space.

If disk space is low, move the index location:

Move-SPEnterpriseSearchIndexComponent -SearchApplication $ssa -SearchIndexLocation "D:\SearchIndex"

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Step 8: Rebuild Search Service Application (If Needed)

If the above steps fail, recreate the Search Service Application.

8.1: Delete the Existing Search Service Application

1. Open Central Administration.
2. Navigate to Manage Service Applications.
3. Select Search Service Application and Delete it.

8.2: Create a New Search Service Application

1. Open Central Administration > Manage Service Applications.
2. Click New > Search Service Application.
3. Provide:
   • Service Name (e.g., Search_Service_New).
   • Service Account (Select an existing or create a new one).
4. Click OK, then perform a Full Crawl.

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Step 9: Restart IIS and SharePoint Timer Job

Restart IIS and the Timer Job to refresh configurations.

9.1: Restart IIS

iisreset /noforce

9.2: Restart SharePoint Timer Job

Restart-Service -Name SPTimerV4

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Step 10: Monitor Search Health Regularly

To prevent future index corruption:

1. Schedule Regular Crawls:
   • Navigate to Search Service Application > Content Sources.
   • Configure Incremental Crawls every 15-30 minutes.
2. Check Crawl Logs Weekly:
   • Open Central Administration > Search Crawl Logs.
3. Monitor Disk Space:
   • Ensure the index location has sufficient free space.

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