Microsoft-Windows-Defrag

Event	Title	Channel	Sample	Rule
258	The storage optimizer successfully completed shrink on (C:)	Application	Y	N
262	The storage optimizer skipped slab consolidation on OS (C:) because: Slab size …	Application	Y	N
264	Event ID 264	Application	Y	N

Event ID 258: The storage optimizer successfully completed shrink on (C:)

Channel: Application

Fields #

Name	Description
`Data_0`
`Data_1`
`Data`
`Binary`

Example Event #

{
  "system": {
    "provider": "Microsoft-Windows-Defrag",
    "guid": "",
    "event_source_name": "",
    "event_id": 258,
    "version": 0,
    "level": 0,
    "task": 0,
    "opcode": 0,
    "keywords": 36028797018963968,
    "time_created": "2026-06-13T06:04:35.3053366+00:00",
    "event_record_id": 776,
    "correlation": {},
    "execution": {
      "process_id": 0,
      "thread_id": 0
    },
    "channel": "Application",
    "computer": "telemetry-DC-a.cell-a.ludus.domain",
    "security": {
      "user_id": ""
    }
  },
  "event_data": {
    "Data_0": "retrim",
    "Data_1": "Windows 2022 (C:)"
  },
  "message": "The storage optimizer successfully completed retrim on Windows 2022 (C:)"
}

Event ID 262: The storage optimizer skipped slab consolidation on OS (C:) because: Slab size is too small.

Channel: Application
Level: Informational

Fields #

Name	Description
`Data`
`Binary`

Example Event #

{
  "system": {
    "provider": "Microsoft-Windows-Defrag",
    "guid": "",
    "event_source_name": "",
    "event_id": 262,
    "version": 0,
    "level": 4,
    "task": 0,
    "opcode": 0,
    "keywords": 36028797018963968,
    "time_created": "2026-01-28T03:03:30.594963+00:00",
    "event_record_id": 260,
    "correlation": {},
    "execution": {
      "process_id": 5876,
      "thread_id": 0
    },
    "channel": "Application",
    "computer": "JD-commando",
    "security": {
      "user_id": ""
    }
  },
  "event_data": {
    "Data": [
      "slab consolidation",
      "OS (C:)",
      "Slab size is too small. (0x8900002D)"
    ],
    "Binary": "LQAAiX8EAAARAgAAFAIAACI2uULZsb04GwcAAAAAAAAAAAAA"
  },
  "message": "The storage optimizer skipped slab consolidation on OS (C:) because: Slab size is too small. (0x8900002D)"
}

References #

Example event sourced from https://github.com/NextronSystems/evtx-baseline

Event ID 264

Channel: Application
Level: Informational

Fields #

Name	Description
`Data_0`
`Data_1`
`Data_2`
`Binary`

Example Event #

{
  "system": {
    "provider": "Microsoft-Windows-Defrag",
    "guid": "",
    "event_source_name": "",
    "event_id": 264,
    "version": 0,
    "level": 4,
    "task": 0,
    "opcode": 0,
    "keywords": 36028797018963968,
    "time_created": "2026-05-29T13:00:11.3544677+00:00",
    "event_record_id": 976,
    "correlation": {},
    "execution": {
      "process_id": 0,
      "thread_id": 0
    },
    "channel": "Application",
    "computer": "telemetry-DC-c.cell-c.ludus.domain",
    "security": {
      "user_id": ""
    }
  },
  "event_data": {
    "Data_0": "retrim",
    "Data_1": "Windows 2022 (C:)",
    "Data_2": "The user cancelled the operation. (0x89000006)"
  },
  "message": "The storage optimizer couldn't complete retrim on Windows 2022 (C:) because: The user cancelled the operation. (0x89000006)"
}