Hotfix for certain devices to support MSI-X interrupt mode in Windows 8.1 or Windows Server 2012 R2

This article describes a hotfix for Peripheral Component Interconnect (PCI) bus driver improvements in Windows 8.1 or Windows Server 2012 R2 to support Message Signaled Interrupts (MSI-X). The hotfix has a prerequisite.


Assume that you mount an MSI-X device to a computer that is running Windows 8.1 or Windows Server 2012 R2. In this situation, MSI-X is not enabled, and you are in the legacy interrupt mode.


To resolve this issue, we have released a hotfix. Even though this issue is observed only in Windows 8.1 or Windows Server 2012 R2, the hotfix also applies to Windows RT 8.1. 

Hotfix information

Important If you install a language pack after you install this hotfix, you must reinstall this hotfix. Therefore, we recommend that you install any language packs that you need before you install this hotfix. For more information, see Add language packs to Windows.

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 this specific problem.

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, submit a request to 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 website: 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.


To apply this hotfix, you must have April 2014 update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 (2919355) installed in Windows 8.1 or Windows Server 2012 R2.

Registry information

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

Restart requirement

You may have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.
File information


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


See the terminology that Microsoft uses to describe software updates.

Article ID: 3070746 - Last Review: Jul 14, 2015 - Revision: 1