Windows CBS (Component-Based Servicing) log
Windows servicing log (CBS.log / CbsPersist*.log). Surfaces component-store corruption, SFC/DISM repair activity, and servicing outcomes. High-volume routine narration is dropped at collection, including the per-package applicability census (installed-update inventory answers which updates are present). Narration that is kept lands at Debug, progress summaries at Verbose, and outcomes at their own severity. Query at severity >= Info for normal investigation, and drop to Verbose or Debug inside a known servicing window.
Feed id: win.servicing.cbs.
Channels
This feed reads a servicing log file on the endpoint rather than an event channel. Each reason below names the file it was read from.
Curated reasons
Severity here is what the condition is worth to the person holding the ticket, not the level the provider stated for itself.
win_component_store_assembly_missing
A component assembly is missing from the store.
Severity: Notice
Impact: Windows will usually repair this automatically.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_corrupt_blocks_package
A Windows package failed to apply because the component store is corrupt.
Severity: Warning
Impact: Updates will keep failing on this machine until the component store is repaired.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_corruption_recurrence
Windows reported how often component-store corruption has been detected.
Severity: Notice
Impact: None directly. A rising count suggests the underlying cause is not being fixed.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_file_repaired
Windows repaired a file from its component store or backup.
Severity: Notice
Impact: None. The file was restored.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_flag_corruption_suspected
Windows suspects component-store file-flag corruption.
Severity: Notice
Impact: None established. The event records a suspicion, not a finding.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_payload_corrupt
A payload file in the component store is corrupt.
Severity: Notice
Impact: Windows will usually repair this automatically.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_payload_unrepairable
Windows could not repair a damaged payload file.
Severity: Warning
Impact: Servicing operations needing this payload will fail until it is restored.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_repair_completed
Windows repaired all recorded component-store corruption.
Severity: Notice
Impact: None. The store is consistent again.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_repair_unavailable
Windows could not repair a damaged component.
Severity: Warning
Impact: Updates touching this component are likely to fail until it is repaired manually.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_reprojection_failed
Windows could not reproject a component.
Severity: Notice
Impact: Usually none: the operation is normally retried.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_scan_found_corruption
A component-store scan detected corruption.
Severity: Notice
Impact: Windows updates may fail later if the damage is not repaired. Detection alone does not mean anything is currently broken.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_scan_repaired_corruption
A component-store scan repaired corruption it found.
Severity: Notice
Impact: None. The damage was fixed.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_source_missing
A servicing operation could not find the source files it needed.
Severity: Warning
Impact: Repair or install will keep failing until a valid source is supplied.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_component_store_sxs_corrupt
The side-by-side component store is corrupt.
Severity: Warning
Impact: Servicing operations may fail until the store is repaired.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_commit_skipped_reboot_required
A servicing change was deferred because a reboot is pending.
Severity: Notice
Impact: The change applies after the next reboot.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_delta_patch_failed
A component delta patch could not be applied.
Severity: Notice
Impact: Usually none: Windows falls back to a full payload.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_duplicate_update_name
Windows found a duplicate update name in a package.
Severity: Notice
Impact: None established. It may indicate a store inconsistency.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_manifest_malformed
A component manifest is malformed.
Severity: Notice
Impact: Operations touching that component may fail.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_manifest_unparseable
Windows could not parse a package manifest.
Severity: Debug
Impact: That optional feature may not be installable.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_package_change_reported
A Windows package was added, removed or updated.
Severity: Debug
Impact: None on its own.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_package_stage_failed
A Windows package could not be staged for installation.
Severity: Warning
Impact: That update will not install until the underlying cause is fixed.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_session_finalized
A Windows servicing session started and finished.
Severity: Debug
Impact: None. This is a liveness marker.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_startup_package_failed
A Windows package failed during startup processing.
Severity: Notice
Impact: That package is not installed. Patching status is better read from the update client.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_servicing_update_package_create_failed
Windows could not create an update package.
Severity: Warning
Impact: That update will not install until the underlying cause is fixed.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
win_sfc_repairing_components
System File Checker started repairing components.
Severity: Notice
Impact: None on its own.
Log file: C:\Windows\Logs\CBS\CBS.log
Fields it can set: win.servicing.cbs.component, win.servicing.cbs.corrupt_component, win.servicing.cbs.corrupt_file, win.servicing.cbs.detected_corruption, win.servicing.cbs.repaired_corruption, win.servicing.cbs.unrepairable_file
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