π ~1 min read
Table of contents
Symptom & Impact
The Host Compute Service on Windows Server 2019 fails to start, so Windows containers cannot launch. Container runtimes report HNS or HCS errors, CI agents fail to schedule build jobs, and orchestrator nodes get cordoned by the platform.
Environment & Reproduction
Reproduce after a containerd or HNS configuration change, broken vSwitch, or missing Containers feature components. Inspect HCS and HNS event channels.
Get-Service -Name containers
Get-WinEvent -LogName System -MaxEvents 40
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 10
Root Cause Analysis
Causes include missing Containers Windows feature, unhealthy Host Network Service, conflicting third-party network filter driver, or invalid container image references in HCS state.
Quick Triage
Capture HCS service state, HNS state, and Containers feature install state before remediation.
sc.exe query containers
Get-Service -Name containers | Select-Object Status,StartType
Get-EventLog -LogName System -Newest 30 | Where-Object {$_.Source -match 'containers'}
Step-by-Step Diagnosis
Inspect HCS events, list Windows features, and validate vSwitch health.
Get-WinEvent -LogName System -MaxEvents 50 | Where-Object {$_.ProviderName -match 'containers'} | Select TimeCreated,Id,LevelDisplayName,Message
sc.exe qfailure containers
sfc /verifyonly

Solution β Primary Fix
Repair the Containers feature, reset HNS state, and restart HCS so containers can create namespaces cleanly.
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Restart-Service -Name containers -Force
Get-Service -Name containers | Select-Object Status,StartType
Get-WinEvent -LogName System -MaxEvents 20 | Where-Object {$_.ProviderName -match 'containers'}

Solution β Alternative Approaches
If a third-party network driver blocks HCS, remove it temporarily and rebuild HNS configuration.
sc.exe config containers start= auto
sc.exe failure containers reset= 86400 actions= restart/60000/restart/60000/run/1000
Restart-Service -Name containers -Force
Verification & Acceptance Criteria
HCS and HNS run, test container starts succeed, and CI nodes return to ready in the orchestrator.
Get-Service -Name containers
Get-WinEvent -LogName System -MaxEvents 25 | Where-Object {$_.ProviderName -match 'containers' -and $_.LevelDisplayName -eq 'Error'}
Test-NetConnection -ComputerName localhost -Port
Rollback Plan
Restore the previous HNS configuration export and reinstall the previously certified third-party driver build.
Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 5
wbadmin get versions
# Restore previous configuration export if available
Prevention & Hardening
Patch HCS on a tracked cadence, certify network filter drivers, and back up HNS configuration regularly.
Get-Service -Name containers | Export-Clixml C:/Temp/containers-baseline.xml
Get-WinEvent -LogName System -MaxEvents 50 > C:/Temp/containers-events.txt
Get-ScheduledTask | Where-Object {$_.TaskName -match 'containers'}
Related Errors & Cross-Refs
Related to events 17, 21, and HNS-Networking error entries.
Related tutorial: View the step-by-step tutorial for Windows Server 2019.
View all Windows Server 2019 tutorials on the Tutorials Hub β
Browse all common problems & solutions on the Tutorials Hub.
References & Further Reading
Microsoft Learn references for Host Compute Service troubleshooting and Windows containers on Windows Server 2019.
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