Microsoft KB Archive/937624

= After you turn on User Account Control in Windows Vista, programs may be unable to access some network locations =

Article ID: 937624

Article Last Modified on 7/20/2007

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APPLIES TO


 * Windows Vista Home Basic
 * Windows Vista Home Premium
 * Windows Vista Ultimate
 * Windows Vista Business
 * Windows Vista Enterprise
 * Windows Vista Starter
 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Ultimate 64-bit Edition
 * Windows Vista Business 64-bit Edition
 * Windows Vista Enterprise 64-bit Edition
 * Windows Vista Home Basic N 64-bit Edition
 * Windows Vista Business N 64-bit Edition

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Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SYMPTOMS
After you turn on User Account Control in Windows Vista, programs may be unable to access some network locations. This problem may also occur when you use the command prompt to access a network location.

Note To turn on User Account Control, you click Allow in a User Account Control dialog box.



CAUSE
This problem occurs because User Account Control treats members of the Administrators group as standard users. Therefore, network shares that are mapped by logon scripts are shared with the standard user access token instead of with the full administrator access token.

When a member of the Administrators group logs on to a Windows Vista-based computer that has User Account Control enabled, the user runs as a standard user. Standard users are members of the Users group. If you are a member of the Administrators group and if you want to perform a task that requires a full administrator access token, User Account Control prompts you for approval. For example, you are prompted if you try to edit security policies on the computer. If you click Allow in the User Account Control dialog box, you can then complete the administrative task by using the full administrator access token.

When an administrator logs on to Windows Vista, the Local Security Authority (LSA) creates two access tokens. If LSA is notified that the user is a member of the Administrators group, LSA creates the second logon that has the administrator rights removed (filtered). This filtered access token is used to start the user’s desktop. Applications can use the full administrator access token if the administrator user clicks Allow in a User Account Control dialog box.

If a user is logged on to Windows Vista and if User Account Control is enabled, a program that uses the user’s filtered access token and a program that uses the user’s full administrator access token can run at the same time. Because LSA created the access tokens during two separate logon sessions, the access tokens contain separate logon IDs.

When network shares are mapped, they are linked to the current logon session for the current process access token. This means that, if a user uses the command prompt (Cmd.exe) together with the filtered access token to map a network share, the network share is not mapped for processes that run with the full administrator access token.



RESOLUTION
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To resolve this problem, configure the EnableLinkedConnections registry value. This value enables Windows Vista to share network connections between the filtered access token and the full administrator access token for a member of the Administrators group. After you configure this registry value, LSA checks whether there is another access token that is associated with the current user session if a network resource is mapped to an access token. If LSA determines that there is a linked access token, it adds the network share to the linked location.

To configure the EnableLinkedConnections registry value, follow these steps:  Click Start, type regedit in the Start Search box, and then press ENTER. Locate and then right-click the following registry subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System

 Point to New, and then click DWORD Value. Type EnableLinkedConnections, and then press ENTER. Right-click EnableLinkedConnections, and then click Modify. In the Value data box, type 1, and then click OK.</li> Exit Registry Editor, and then restart the computer.</li></ol>

Keywords: kbtshoot kbprb kbexpertiseinter KB937624

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