SYSTEM_SCAN_AT_RAISED_IRQL_CAUGHT_IMPROPER_DRIVER_UNLOAD
Improper driver unload caught at raised IRQL
SYSTEM_SCAN_AT_RAISED_IRQL_CAUGHT_IMPROPER_DRIVER_UNLOAD is bug check code 0x000000D4. This bug check is a verifier-style finding: a driver unloaded without cancelling pending operations. The key issue is lifetime management of callbacks, timers, DPCs, work items, IRPs, or device objects that can still be touched after unload.
How to read it in a dump
- The name already identifies driver unload as the likely contract violation.
- Find pending operations that outlive DriverUnload, device removal, or failure cleanup.
- IRQL matters because some checks run while normal blocking cleanup is no longer possible.
What to check
- Audit DriverUnload, EvtDeviceReleaseHardware, cancel paths, timers, DPCs, work items, and queued IRPs.
- Run Driver Verifier on the suspect driver in a test system.
- Check for use-after-unload or callbacks not deregistered before unload.
References
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