What does BSOD 165 (ACPI_BIOS_ERROR) mean?

 
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CNSS_FILE_SYSTEM_FILTER FP_EMULATION_ERROR

ACPI_BIOS_ERROR

ACPI_BIOS_ERROR meaning

ACPI_BIOS_ERROR is bug check 0x000000A5. Windows found that the firmware ACPI implementation is not compliant enough for the operation being performed. Parameter 1 selects the incompatibility class, and the remaining parameters describe the affected table, resource, namespace object, or ACPI method.

How to analyze the result

Start with Parameter 1 and the exact firmware revision. Save the ACPI tables, BIOS/UEFI version, platform model, and the stack or setup phase in which the failure occurred. Compare the installed firmware with the system vendor release notes rather than applying generic driver changes.

  • Preserve the complete dump, all four parameters, Windows build, loaded modules, and the event timeline before changing drivers or firmware while investigating this result.
  • Run !analyze -v and follow the parameter-specific objects and the stack associated with this result rather than relying only on the symbolic name or a single probable-cause line.
  • Compare multiple dumps when available; a stable instruction or object path associated with this result is stronger evidence than a module that appears only after earlier corruption.

Recovery boundary

Update firmware only through the platform vendor workflow. If no compliant firmware exists, the durable fix belongs to the firmware or platform configuration; disabling ACPI is a legacy setup workaround and is not a normal recovery strategy for current systems.

Official references

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