Fulltext filter daemon host (FDHost) process has stopped abnormally

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Fulltext filter daemon host (FDHost) process has stopped abnormally

zoggling

SSCrazy

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August 17, 2026 at 8:10 am

#4936188
We have performed a side-by-side upgrade, from SQL Server 2016 to 2022 Developer Edition, for our instance hosting our Azure DevOps catalogs. Having backed up and restored all of our Azure DevOps (formerly TFS) catalogs/databases to the new database server, we have been experiencing the following severity 17 alert several times per day:
"The fulltext filter daemon host (FDHost) process has stopped abnormally. This can occur if an incorrectly configured or malfunctioning linguistic component, such as a wordbreaker, stemmer or filter has caused an irrecoverable error during full-text indexing or query processing. The process will be restarted automatically."
Full-text search was not enabled on our 2016 instance, but appeared to be required for the new version of Azure DevOps.
Things we have tried/observed:
- We have established the FDHost crashes can occur every few seconds, with one observed period lasting approximately 28 minutes.
- We have checked the SQL Server Full-Text metadata:
  - Confirmed sys.fulltext_indexes contains entries.
  - Confirmed sys.fulltext_catalogs contains TeamFoundationServer14FullTextCatalog.
  - Confirmed sys.dm_fts_index_population contains active populations.
  - Confirmed all populations remain stuck at Starting with completion_type_description = NONE.
- We have checked Azure DevOps Search separately, and ran TriggerCollectionIndexing.ps1 against the catalogs. No change.
- We have checked Azure DevOps Search indexing status using ExtensionInstallIndexingStatus.ps1 and RecentIndexingActivity.ps1. No change.
- We have established that Azure DevOps Search reports no current/recent indexing activity, suggesting the SQL Server FDHost problem is probably separate from the Azure DevOps Elasticsearch/Search indexing subsystem.
Further Details
- Version Azure DevOps Server 25H2 (AzureDevopsServer_20260304.1)
- Microsoft SQL Server 2022 (RTM-CU24-GDR) (KB5089900) - 16.0.4252.3 (X64) Apr 26 2026 07:08:29 Copyright (C) 2022 Microsoft Corporation Developer Edition (64-bit) on Windows Server 2025 Standard 10.0 <X64> (Build 26100: ) (Hypervisor)

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Site Owners SSC Guru Points: 80222 More actions · Answer 1

Thanks for posting your issue and hopefully someone will answer soon.

This is an automated bump to increase visibility of your question.

Jo Pattyn SSC-Dedicated Points: 32714 More actions · Answer 2

Not sure about sql 2022 but sql 2025 had a fix lately about full text and word documents

zoggling SSCrazy Points: 2275 More actions · Answer 3

Is this likely to relate to Word documents that have been uploaded to DevOps? If so, does anyone please know what we can do to resolve this?

Does DevOps Server 25H2 definitely require Full-text Search? Or can we just disable the service altogether?

Jo Pattyn SSC-Dedicated Points: 32714 More actions · Answer 4

not sure, running devops on premises could be a nich situation. Contact Microsoft? Regarding the sql 2025 bug https://sqlserverperformace.blogspot.com/2026/04/sql-server-2025-cu4-full-text-search.html

Steve Jones - SSC Editor SSC Guru Points: 743306 More actions · Answer 5

No idea if this is required for the local AzDO server, but it might be. People upload things and there is likely some FTS used to search through documents or perhaps find wildcard items in work items, boards, etc.

You might contact MS Support here.