After you change the SATA mode of disk devices to use the AHCI specification on a Windows Server 2008-based or Windows Vista-based computer, the computer or certain applications randomly stop responding for 60 seconds or longer

On a computer that is running Windows Server 2008 or Windows Vista, you change the Serial Advanced Technology Attachment (SATA) mode of a disk device to use the Advanced Host Controller Interface (AHCI) specification in the BIOS setup stage. After the setting takes effect, the computer randomly stops responding for 60 seconds or longer.

Notes

This problem occurs more frequently under heavy disk I/O conditions.

Any application that performs I/O operations on SATA/AHCI devices may also stop responding. For example, Windows Explorer may stop responding when it performs I/O operations on SATA/AHCI devices.

This problem occurs because of a race condition between the interrupt handler in the AHCI driver (Msahci.sys) and the disk device. Therefore, the AHCI driver does not detect that some I/O requests are completed until the time-out handler collects these requests 60 seconds later. The race condition may occur because the driver does not follow the AHCI specifications to access related registers.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, your computer must be running one of the following Windows operating systems:

• Windows Vista Service Pack 1 (SP1)
• Windows Vista Service Pack 2 (SP2)
• Windows Server 2008
• Windows Server 2008 Service Pack 2 (SP2)

For more information about how to obtain a Windows Vista service pack, click the following article number to view the article in the Microsoft Knowledge Base: For more information about how to obtain a Windows Server 2008 service pack, click the following article number to view the article in the Microsoft Knowledge Base:

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and times for these files are listed in Coordinated Universal Time (UTC). The dates and times for these files on your local computer are displayed in your local time and with your current daylight saving time (DST) bias. Additionally, the dates and times may change when you perform certain operations on the files.

Windows Vista and Windows Server 2008 file information notes

Important Windows Vista hotfixes and Windows Server 2008 hotfixes are included in the same packages. However, only "Windows Vista" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both of these operating systems, select the hotfix that is listed under "Windows Vista" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.

• The files that apply to a specific product, SR_Level (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.
  Collapse this tableExpand this table

  Version	Product	SR_Level	Service branch
  6.0.600 0 . 20xxx	Windows Vista	RTM	LDR
  6.0.600 1 . 22xxx	Windows Vista and Windows Server 2008	SP1	LDR
  6.0.600 2 . 22xxx	Windows Vista and Windows Server 2008	SP2	LDR

• Service Pack 1 is integrated into the release version of Windows Server 2008. Therefore, RTM milestone files apply only to Windows Vista. RTM milestone files have a 6.0.0000.xxxxxx version number.
• The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are critical to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows Server 2008 and of Windows Vista

For all supported x64-based versions of Windows Server 2008 and of Windows Vista

For all supported IA-64-based versions of Windows Server 2008

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

For more information about the AHCI specification, visit the following Intel Web site: For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: -

Additional file information

Additional file information for Windows Vista and for Windows Server 2008

Additional files for all supported x86-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported x64-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported IA-64-based versions of Windows Server 2008