Windows may fail to boot from an iSCSI drive if networking hardware is changed

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Consider the following scenario:

• You have a computer that is running Windows Server 2008 R2.
• The computer is configured to boot from an iSCSI disk.
• A secondary network adapter is configured for the iSCSI disk. This adapter is not configured when Windows is installed on the iSCSI disk.
• You boot the computer from the secondary iSCSI network adapter. Or the iSCSI network adapter is re-enumerated by Windows. For example, if the computer is running IBM UEFI firmware Version 1.40, the iSCSI network adapter will be re-enumerated if you upgrade the firmware to a later version.

In this scenario, you may receive the following Stop error message:
Note

• The four parameters in this Stop error message may vary, depending on the configuration of the computer.
• Not all "0x0000007B" Stop error messages are caused by this problem.

In Windows Server 2008 R2, a new NDIS Light Weight Filter (LWF) driver is introduced called “WFP Lightweight Filter”. When Windows is installed on a local disk, this filter driver is installed and bound to all network adapters, including the network adapter to be used for iSCSI boot. If Windows is installed directly on an iSCSI disk, Windows Setup makes sure that the LWF driver does not get installed on the network adapter used with iSCSI boot. If, however, there are secondary iSCSI boot adapters (like in a fail-over environment) in the machine that are not configured for such roles during the Windows installation (e.g. an iSCSI Bios Firmware Table (iBFT) is not presented at install time or such devices are added later), the LWF driver is installed and bound on all such secondary or fail-over devices.

The NDIS LWF driver is neither a boot-start driver nor is it compatible with paging I/O. When any of the above systems, where NDIS LWF driver is bound to an iSCSI boot adapter, are started, Windows may fail to boot and/or causes a bugcheck 0x7B (INACCESSIBLE_BOOT_DEVICE).

Note The preferred method of creating an iSCSI boot image for deployment is to perform a standard Windows Setup-based installation from Windows installation media, and then if desired to capture the image for deployment to systems with identical iSCSI boot hardware.

To resolve the problem, apply the hotfix before the iSCSI network adapter is replaced or changed. If the computer is running IBM UEFI firmware Version 1.40, apply the hotfix before the IBM firmware is upgraded.

If you do not apply the hotfix, follow the steps in the Workaround section to resolve the problem.

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, you must be running one of the following operating systems:

• Windows Server 2008 R2
• Windows Server 2008 R2 Service Pack 1 (SP1)

For more information about how to obtain a Windows 7 or Windows Server 2008 R2 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 the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.

Windows 7 and Windows Server 2008 R2 file information notes

• The files that apply to a specific product, milestone (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	Milestone	Service branch
  6.1.760 0 . 16xxx	Windows Server 2008 R2	RTM	GDR
  6.1.760 0 . 21xxx	Windows Server 2008 R2	RTM	LDR
  6.1.760 1 . 17xxx	Windows Server 2008 R2	SP1	GDR
  6.1.760 1 . 21xxx	Windows Server 2008 R2	SP1	LDR

• GDR service branches contain only those fixes that are widely released to address widespread, extremely important issues. LDR service branches contain hotfixes in addition to widely released fixes.
• 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 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.

For all supported x64-based versions of Windows Server 2008 R2

For all supported IA-64-based versions of Windows Server 2008 R2

To work around this issue without applying the hotfix, before creating an iSCSI bootable Windows image to be deployed on an iSCSI target or after configuring the secondary/fail-over boot-adapters, unbind NDIS LWF driver from any network adapters being used for iSCSI boot.

NDIS LWF driver can be unbound from the target miniport via BindView or NvspBind (among other tools).

Bindview is graphic user interface tool available from the Windows WDK. For instructions how to download the latest Windows WDK, please visit:
Nvspbind is a command line tool available from the following location:
To unbind the NDIS LWF driver using BindView, do the following:

1. Build the BindView sample from Windows Developer Kit (WDK). It is located in the <WDK Root>\ src\network\config\bindview directory, where <WDK Root> is the root directory where WDK is installed.
2. Run BindView application built in step one above.
3. In “Show bindings for” – Select “All Services”
4. You will see “WFP Lightweight filter” node. Expand it to see its binding paths.
5. Right-Click on “Binding Path #” for the iSCSI boot NIC and select “Disable”. If the Disable option is not available, it means the binding is already disabled.

To unbind the NDIS LWF Driver with Nvspbind, do the following:

1. Identify the GUID for the boot NIC by displaying the NIC information with the command: nvspbind –n
   For example each NIC will appear similar to the following:
   {091786BC-FC48-4CDB-B7C5-94994C83C8CF}
   "vmbus\{f8615163-df3e-46c5-913f-f2d2f965ed0e}"
   "Microsoft Virtual Machine Bus Network Adapter #2"
   "iSCSI1":
2. Determine if NDIS LWF driver is enabled on the NIC with the command: nvspbind.exe {guid}
   For example: nvspbind {091786BC-FC48-4CDB-B7C5-94994C83C8CF}
3. When enabled the NDIS LWF driver will appear as follows:
   enabled: ms_wfplwf (WFP Lightweight Filter)
4. Disable the NDIS LWF driver with the command: nvspbind.exe /d {guid} ms_wfplwf
   For Example: nvspbind /d {091786BC-FC48-4CDB-B7C5-94994C83C8CF} ms_wfplwf
5. Verify the NDIS LWF driver was disabled with the command: nvspbind.exe {guid}
   For example: nvspbind {091786BC-FC48-4CDB-B7C5-94994C83C8CF}
6. When disabled the NDIS LWF driver will appear as follows:
   disabled: ms_wfplwf (WFP Lightweight Filter)

For additional information and examples on how to use Nvspbind please refer to the Readme.doc included in Nvspbind tool download.

Once LWF is unbound successfully from all boot-devices, proceed to create an image for deployment as usual.

Note

• The user must have Administrative privileges to perform the unbind operations.
• ALL network adapters that will be used for booting (like primary and secondary/failover boot-adapters) must have NDIS LWF driver unbound from them.

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

For more information about iSCSI Boot, refer to the following:For more information about a related issue, click the following article number to view the article in the Microsoft Knowledge Base: 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 Server 2008 R2

Additional files for all supported x64-based versions of Windows Server 2008 R2

Additional files for all supported IA-64-based versions of Windows Server 2008 R2

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