A user name that contains Unicode characters is not handled correctly in Windows Vista and Windows Server 2008 during EAP authentication

On a Windows Vista-based or a Windows Server 2008-based computer, you try to establish a connection to in order to access a local network. If the user name of the user account contains Unicode characters, the connection attempt fails the Extensible Authentication Protocol (EAP) authentication. Therefore, you cannot access the local network.

This problem occurs because of the EAPHost architecture in Windows Vista and in Windows Server 2008. When you try to authenticate, the EAPHost converts the EAP ID message to Unicode. However, the server tries to read the EAP ID message as ASCII. Because the ASCII encoding mechanism for characters from 128 to 255 differs from the mechanism in Unicode, the EAP authentication fails if the user name includes Unicode characters from 128 to 255.

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 this specific problem. 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

The following list contains prerequisites for the hotfix:

• Windows Vista
• Windows Vista SP1
• Windows Server 2008

Restart requirement

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

Hotfix replacement information

This hotfix does not replace a previously released hotfix..

Registry information

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: To enable this hotfix, follow these steps:

1. Click Start, type regedit, and then press ENTER.
2. Locate the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\EapHost\Configuration
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type IdentityEncodingFormat, and then press ENTER.
5. On the Edit menu, click Modify.
6. Type 1, and then click OK .
7. Exit Registry Editor.

File information

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 Vista and Windows Server 2008 file information note

• The files that apply to a specific product or milestone (RTM, SPn) can be identified by examining the file version numbers as shown in the following table.

  Version	Product	Milestone	Service branch
  6.0.6000.20xxx	Windows	RTM	LDR
  6.0.6001.22xxx	Windows Vista SP1 and Windows Server 2008 SP1	SP1	LDR

• Service Pack 1 is integrated into 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 and the .mum files that are installed in each environment are listed separately in the "Additional file information for Windows Server 2008 and for Windows Vista" 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 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 Itanium-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 EAPHost architecture, visit the following Microsoft 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 for Windows Server 2008 and Windows Vista

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

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

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