"Stop 0x000000A5 the ACPI BIOS in the system is not fully compliant with the ACPI specification" error message when the computer resumes from hibernation


You may experience any one of the following symptoms:
  • Your computer automatically restarts.
  • After you log on, you receive the following error message:
    Microsoft Windows

    The system has recovered from a serious error.
    A log of this error has been created.

    Please tell Microsoft about this problem.
    We have created an error report that you can send to help us improve Microsoft Windows. We will treat this report as confidential and anonymous.

    To see what data this error report contains, click here.
    If the error message still appears and if you want to see the data that the error report contains, click the click here link at the bottom of the message box. You then see error signature information that may be similar to:
    BCCode : 000000A5 BCP1 : 00000011 BCP2 : 00000006
    BCP3 : 00000000
    BCP4 : 00000000 OSVer : 5_1_2600 SP : 0_0 Product : 256_1
  • You receive the following "Stop" error message on a blue screen:
    A problem has been detected and Windows has been shut down to prevent damage to your computer...
    Technical information:

    *** STOP: 0x000000A5 (0x00000011, 0x00000006, 0x00000000, 0x00000000)

    Bug Check Symbolic Name
  • When you view the system log in Event Viewer, you may notice an event ID 1003 entry with information that is similar to:
    Date: date
    Source: System
    Error Time: time
    Category: (102)

    Type: Error
    Event ID: 1003

    User: N/A

    Computer: COMPUTER
    Description: Error code 000000A5, parameter1 00000011, parameter2 00000006, parameter3 00000000, parameter4 00000000. For more information, see Help and Support Center at http://support.microsoft.com. Data: 0000: 53 79 73 74 65 6d 20 45 System E 0008: 72 72 6f 72 20 20 45 72 rror Er 0010: 72 6f 72 20 63 6f 64 65 ror code 0018: 20 30 30 30 30 30 30 35 00000A5 0020: 30 20 20 50 61 72 61 6d 0 Param 0028: 65 74 65 72 73 20 66 66 eters ff 0030: 66 66 66 66 64 31 2c


  • The symptoms of a Stop error vary according to your computer's system failure options. For more information about how to configure system failure options, click the following article number to view the article in the Microsoft Knowledge Base:

    307973 How to configure system failure and recovery options in Windows

  • The four parameters that are included in the error signature information (BCP
    x) and inside the parentheses of the technical information for the Stop error may vary according to the computer's configuration.
  • Not all Stop 0x000000A5 errors are caused by the problem that is described in this article.
    For more information about how to troubleshoot Stop 0x000000A5 errors, click the following article number to view the article in the Microsoft Knowledge Base:

    314830 "Stop 0x000000A5" error when you are installing Windows XP


This problem may occur if you add random access memory (RAM) to the computer while it is in hibernation. When the computer resumes from hibernation and loads the Hiberfil.sys file, Microsoft Windows detects the change in memory state, and then you receive the error message.


To resolve this problem, restart your computer.

If the problem persists, start the computer by using the Windows CD or by using an emergency startup disk, and then delete the Hiberfil.sys file. To do this, follow these steps:
  1. Insert your Windows XP CD-ROM into the computer's CD-ROM drive or DVD-ROM drive, and then restart your computer from the CD-ROM.
    Some computers may require that you modify the basic input/output system (BIOS) settings before you can start the computer from a CD-ROM. For information about how to modify BIOS, see your computer documentation.
  2. When the "Welcome to Setup" screen appears, press R to start Recovery Console.

  3. If your computer is configured for dual booting or multiple booting, select the relevant Windows XP installation.

  4. When you are prompted to do so, type the administrator password, and then press ENTER.
    Note By default, the administrator password is blank in Windows XP Home Edition.

  5. By default, Hiberfil.sys is typically located in the root directory (C:\). At the command prompt, type del hiberfil.sys, and then press ENTER.
  6. Restart the computer.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

Always shut down your computer before you add RAM.


For more information about how to use the Recovery Console to repair problems, click the following article number to view the article in the Microsoft Knowledge Base:

307654 How to install and use the Recovery Console in Windows XP

For more information about hibernation, click the following article number to view the article in the Microsoft Knowledge Base:

305905 Hibernation does not work on a portable computer after Windows XP upgrade and RAM increase