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)