BSOD 0x91 (WIN32K_INIT_OR_RIT_FAILURE): causes and diagnosis

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: Win32k or the raw input thread failed during graphical subsystem initialization.

Could be also:
Constant	Type	OS
ERROR_DIR_NOT_EMPTY	Win32 error	Windows
ETIMEDOUT	errno	Solaris

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PP1_INITIALIZATION_FAILED	UP_DRIVER_ON_MP_SYSTEM

WIN32K_INIT_OR_RIT_FAILURE

Win32k and raw input initialization failure for WIN32K_INIT_OR_RIT_FAILURE

WIN32K_INIT_OR_RIT_FAILURE is bug check code 0x00000091.

This bug check belongs to the session/graphics input path. It points at failure while initializing win32k, the raw input thread, display input plumbing, or session graphics state rather than a normal user-mode window crash.

How to read it in a dump

Check whether the system was starting a session, switching display state, or initializing graphics/input drivers.
Graphics drivers, keyboard/mouse filters, session manager, and win32k stack frames are key evidence.
A user-mode application is usually a symptom, not the direct cause.

What to check

Check display/input filter drivers and recent GPU driver updates.
Compare safe mode and normal boot behavior.
Use kernel symbols to inspect win32k and raw input thread initialization frames.

References

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