Knowledge

ERROR_ACPI_ERROR - 669 (0x29D)

An error occurred in the ACPI subsystem.

Updated: Feb 21, 2026

Technical Background

The ACPI (Advanced Configuration and Power Interface) subsystem is responsible for managing power states and hardware configuration in Windows operating systems. Errors within this subsystem can indicate issues with system hardware or firmware.

Error Details

Error Name: ERROR_ACPI_ERROR Numeric Code: 669 Hex Code: 0x29D

This error code indicates that an unexpected condition has occurred within the ACPI subsystem, which could be due to various reasons such as incorrect hardware configuration, firmware issues, or driver problems.

Common Causes

  • Incorrect hardware configuration
  • Firmware issues
  • Driver problems
  • Power management conflicts

Real-World Context

ACPI errors can manifest in different ways depending on the specific issue. For example, a system might fail to enter sleep mode, experience unexpected restarts, or display error messages related to power states.

Is This Error Critical?

The severity of this error depends on its context and the underlying cause. While it is generally not critical, persistent errors can indicate hardware or firmware issues that may require attention.

How to Diagnose

  1. Review Operation Context: Check if any recent changes were made to hardware or software configurations.
  2. Validate Parameters: Ensure all parameters related to power management are correctly set.
  3. Confirm Object Types: Verify the types of objects involved in the operation, such as devices and power states.
  4. Verify Input Data: Check for any corrupted data that might affect ACPI operations.
  5. Check Limits or Constraints: Confirm that no system limits have been exceeded.

How to Resolve

  1. Correct Parameter Usage: Ensure all parameters are correctly configured according to the documentation.
  2. Adjust Operation Context: Modify the context in which the operation is performed, such as adjusting power settings.
  3. Restore Data: If data corruption is suspected, restore from a backup or reinstall necessary drivers and firmware.
  4. Retry Operation with Valid Inputs: Attempt to perform the operation again with valid inputs.

Developer Notes

Developers should be aware that ACPI errors can be indicative of broader system issues beyond just the subsystem itself. Careful investigation into hardware and firmware configurations is often required to resolve such errors.

Related Errors

  • ERROR_ACPI_TABLE_NOT_FOUND (672, 0x298)
  • ERROR_ACPI_INVALID_TABLE (673, 0x299)
  • ERROR_ACPI_IO_PORT_ACCESS_FAILURE (674, 0x29A)

FAQ

Q: What does the ERROR_ACPI_ERROR error mean?

A: This error indicates an unexpected condition in the ACPI subsystem.

Q: How can I troubleshoot this error?

A: Review recent hardware and software changes, validate parameters, confirm object types, verify input data, and check system limits.

Q: Is this error critical?

A: The severity varies; persistent errors may indicate hardware or firmware issues that require attention.

Summary

The ERROR_ACPI_ERROR (669, 0x29D) is a specific error indicating an unexpected condition in the ACPI subsystem. While not inherently critical, it can be indicative of broader system issues and should be investigated to ensure proper hardware and firmware configurations.