Thursday, May 23, 2013

Unable to access from Network locations after UAC enabled

 

source:  http://support.microsoft.com/kb/937624/en-us

 

Article ID: 937624 - View products that this article applies to.

SYMPTOMS

After you turn on User Account Control in Windows Vista or in Windows 7, 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.

When a member of the Administrators group logs on to a Windows Vista-based computer or to a Windows 7-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 or to Windows 7, 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 or to Windows 7, 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.

WORKAROUND

Important This workaround may make your system unsafe. Microsoft does not support this workaround. Use this workaround at your own risk.

To work around this problem, configure the EnableLinkedConnections registry value. This value enables Windows Vista or Windows 7 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:
  1. Click Start, type regedit in the Start Search box, and then press Enter.
  2. Locate and then right-click the following registry subkey:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
  3. Point to New, and then click DWORD Value.
  4. Type EnableLinkedConnections, and then press Enter.
  5. Right-click EnableLinkedConnections, and then click Modify.
  6. In the Value data box, type 1, and then click OK.
  7. Exit Registry Editor, and then restart the computer.
http://support.microsoft.com/kb/937624/en-us

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