BSOD 51 (UNEXPECTED_INITIALIZATION_CALL): causes and diagnosis

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: An initialization routine was called in an unexpected phase or state.

Could be also:
Constant	Type	OS
ERROR_REM_NOT_LIST	Win32 error	Windows
KERN_POLICY_STATIC	Kern return	Mac
ippStsFeaturesCombination	Intel Ipp Status	Any
EL2HLT	errno	Linux
ENETUNREACH	errno	Mac
EBADR	errno	Solaris

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PHASE1_INITIALIZATION_FAILED	CACHE_MANAGER

UNEXPECTED_INITIALIZATION_CALL

Unexpected kernel initialization call for UNEXPECTED_INITIALIZATION_CALL

UNEXPECTED_INITIALIZATION_CALL is bug check code 0x00000033. This bug check points at initialization sequencing rather than a normal runtime driver error. A component entered an init routine after the expected phase, before prerequisites existed, or in a state that made initialization unsafe.

How to read it in a dump for UNEXPECTED_INITIALIZATION_CALL

Identify the initialization phase on the stack: boot loader handoff, kernel init, driver load, subsystem init, or late reinitialization.
A duplicate call can indicate corrupt state, a wrong driver entry path, or incompatible boot/start ordering.
The failing module and phase are more important than the symbolic name alone.

What to check for UNEXPECTED_INITIALIZATION_CALL

Check boot-start and system-start drivers, filter load order, and recent kernel or driver updates.
Look for duplicate registration or reinitialization paths.
Compare with neighboring init bug checks if the machine fails early in boot.

References for UNEXPECTED_INITIALIZATION_CALL

Dump evidence for UNEXPECTED_INITIALIZATION_CALL

For UNEXPECTED_INITIALIZATION_CALL, preserve the complete dump, the four bug-check parameters, the exact Windows build, loaded-module list, and the event timeline immediately before the stop. AllStat summarizes the condition as “UNEXPECTED_INITIALIZATION_CALL”; that sentence identifies the failure class, while the parameters and stack determine which object, driver, processor, or subsystem instance was involved.

Analysis order for UNEXPECTED_INITIALIZATION_CALL

Run WinDbg !analyze -v, then inspect the documented meaning of each UNEXPECTED_INITIALIZATION_CALL parameter instead of relying only on the probably-caused-by line.
For UNEXPECTED_INITIALIZATION_CALL, find the earliest abnormal event: driver update, firmware change, device reset, storage error, verifier report, resource exhaustion, or application hang connected with unexpected / initialization / call.
For UNEXPECTED_INITIALIZATION_CALL, keep third-party filter, security, storage, graphics, and virtualization drivers in the module inventory; removing evidence before dump analysis can obscure the responsible path.

Do not repeatedly reboot a machine affected by UNEXPECTED_INITIALIZATION_CALL before collecting the dump and event logs. For UNEXPECTED_INITIALIZATION_CALL, recovery actions should follow the component identified by the stack and parameters, not merely the symbolic stop-code name.

Dump evidence for UNEXPECTED_INITIALIZATION_CALL

Analysis order for UNEXPECTED_INITIALIZATION_CALL

Run WinDbg !analyze -v, then inspect the documented meaning of each UNEXPECTED_INITIALIZATION_CALL parameter instead of relying only on the probably-caused-by line.
For UNEXPECTED_INITIALIZATION_CALL, find the earliest abnormal event: driver update, firmware change, device reset, storage error, verifier report, resource exhaustion, or application hang connected with unexpected / initialization / call.
For UNEXPECTED_INITIALIZATION_CALL, keep third-party filter, security, storage, graphics, and virtualization drivers in the module inventory; removing evidence before dump analysis can obscure the responsible path.

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