You cannot access a document library on a Windows SharePoint Services 3.0 or Windows SharePoint Services 2.0 Web site from a client computer that is running one of the following operating systems:

• Windows Vista
• Microsoft Windows XP Service Pack 2 (SP2) or later versions of Windows XP
• The 64-bit version of Windows XP or later versions of Windows XP
• Windows Server 2003 Service Pack 1 (SP1) or later versions of Windows Server

This issue occurs if you use a connection method that uses Windows shell components or Explorer View. For example, you may experience one or more of the following symptoms:

• If you try to map a drive to a document library by using the net use command, you are prompted to type your user name and password. After you type your user name and password, you receive the following error message:
  System error 5 has occurred.
  Access is denied.
• If you try to view a document library by using Explorer View, you are prompted several times to type your user name and password. If you click Cancel, Explorer View displays Web folders.

This behavior occurs if the following conditions are true:

• You connect to the server that is running Windows SharePoint Services 3.0 or Windows SharePoint Services 2.0 from a client computer that is running Windows Vista or Windows XP Service Pack 2 (SP2) or a later version of Windows XP.
• The server is configured to use Basic authentication.

For security purposes, Windows Vista and Windows XP SP2 disable Basic authentication in the Web Distributed Authoring and Versioning (WebDAV) Redirector. Both Explorer View in Windows SharePoint Services and the Windows shell commands that are associated with Windows SharePoint Services use WebDAV redirector technology.

To have us enable Basic authentication on the client computer for you, go to the "Fix it for me" section. If you prefer to fix this problem yourself, go to the "Let me fix it myself" section.

Fix it for me

To fix this problem automatically, click the Fix it button or link. In the File Download dialog box, click Run, and then follow the steps in the Fix it Wizard.




Notes

• This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.
• If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.

Then, go to the "Did this fix the problem?" section.

Let me fix it myself

Windows XP and Windows Server 2003

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 work around this behavior, enable Basic authentication on the client computer. To do this, add the registry entry to the following registry subkey, and then set the entry to a non-zero value: To enable Basic authentication on the client computer, follow these steps:

1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. Locate and then click the following registry key:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
4. On the Edit menu, point to New, and then click DWORD Value.
5. Type UseBasicAuth, and then press ENTER.
6. On the Edit menu, click Modify.
7. In the Value data box, type 1, and then click OK.
   
   Note Basic authentication is enabled if the
   UseBasicAuth
   registry entry is set to a non-zero value. Basic authentication is disabled if the
   UseBasicAuth
   registry entry is not present or if the
   UseBasicAuth
   registry entry is set to 0 (zero).
8. Exit Registry Editor, and then restart the computer.

Windows Vista

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 work around this behavior, enable Basic authentication on the client computer. To do this, add the registry entry to the following registry subkey, and then set the entry to a value of 2 or more: To enable Basic authentication on the client computer, follow these steps:

1. Click Start
   Collapse this imageExpand this image

   
   , type regedit in the Start Search box, and then click regedit.exe in the Programs list.
2. Locate and then click the following registry key:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type BasicAuthLevel, and then press ENTER.
5. On the Edit menu, click Modify.
6. In the Value data box, type 2, and then click OK.
   
   Note The mapping is as follows:
   • 0 - Basic authentication disabled
   • 1 - Basic authentication enabled for SSL shares only
   • 2 or greater - Basic authentication enabled for SSL shares and for non-SSL shares
7. Exit Registry Editor, and then restart the computer.

Did this fix the problem?

• Check whether the problem is fixed. If the problem is fixed, you are finished with this section. If the problem is not fixed, you can contact support (http://support.microsoft.com/contactus) .
• We would appreciate your feedback. To provide feedback or to report any issues with this solution, please leave a comment on the "Fix it for me (http://blogs.technet.com/fixit4me/) " blog or send us an email (mailto:fixit4me@microsoft.com?Subject=KB) .

WebDAV is an extension of Hypertext Transfer Protocol (HTTP), and includes the use of Basic authentication. Basic authentication is one form of user authentication where a user is identified to the server.

When the server is configured to use Basic authentication, the client computer transmits the users' credentials to the server. If the channel is not encrypted, such as in typical HTTP traffic, a malicious user on another computer on the network can possibly intercept the user name and password of that user.

Since a user's credentials can be possibly compromised if they are sent in clear text, Windows Vista and Windows XP SP2 include functionality that permits you to control the use of Basic authentication by the DAV redirector.

The DAV redirector prior to Windows Vista does not support encrypted HTTP, such as HTTPS or Secure Sockets Layer (SSL) resulting in the transmission of the users' credentials without encryption if the server supports Basic authentication. Beginning with Windows Vista the DAV redirector supports SSL and by default disables the use of Basic authentication without SSL enabled.
By default, Basic authentication is disabled in Windows Vista and in Windows XP SP2. When Basic authentication is disabled, either the client computer uses a different authentication method (if the server supports a different authentication method), or the request fails.

For more information about Windows SharePoint Services 3.0, visit the following Microsoft Web site:
For more information about Windows SharePoint Services 2.0, visit the following Microsoft Web site: