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You have a program that uses an IRET or an IRETD instruction that matches the Intel specification. When you run this program in a Windows Server 2008 Hyper-V environment, this program may not execute the IRET or IRETD instruction.
Note This problem occurs only when this program runs in a virtual machine.
Hyper-V emulates the IRET and IRETD instructions that are used in virtual machines. However, these emulated instructions do not support the Nested Task (NT) flag in protected mode.
Note The Intel CPU runs in protected mode.
Service Pack information
To resolve this problem, obtain the latest service pack for Windows Server 2008. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
968849 How to obtain the latest service pack for Windows Server 2008
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.
Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the “Hotfix Request” page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.
To apply this hotfix, the computer must be running Windows Server 2008 with Hyper-V.
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace any other hotfixes.
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
Windows Server 2008 file information notes
The .manifest files and the .mum files that are installed in each environment are listed separately in the "Additional file information for Windows Server 2008" section. These files and their associated .cat (security catalog) files are critical to maintaining the state of the updated component. The .cat files are signed with a Microsoft digital signature. The attributes of these security files are not listed.
For all supported versions of Windows Server 2008 with Hyper-V
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 IRET and IRETD instructions, visit the following Intel Web site:
Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: -
824684 Description of the standard terminology that is used to describe Microsoft software updates
Additional file information for Windows Server 2008
Additional files for all supported versions of Windows Server 2008 with Hyper-V