Microsoft KB Archive/321652

= You receive error message and are continuously prompted for your Windows NT domain credentials in Outlook 2000, Outlook 2002, or Outlook 2007 =

Article ID: 321652

Article Last Modified on 6/1/2007

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APPLIES TO


 * Microsoft Office Outlook 2007
 * Microsoft Outlook 2002 Standard Edition
 * Microsoft Outlook 2000 Standard Edition
 * Microsoft Exchange 2000 Server Standard Edition
 * Microsoft Exchange Server 5.5 Standard Edition

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This article was previously published under Q321652



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
When you start Microsoft Outlook, you may receive one of the following error messages:

Your logon information was incorrect. Check your username and domain, then type your password again. If your account is new or if your administrator requested a password change you need to click Change Password then logon with your new password.

-or-

The logon credentials supplied were incorrect. Make sure your username and domain are correct, then type your password again.

When you start Outlook against your Microsoft Exchange Server mailbox, you receive a prompt for your Windows domain credentials multiple times. After you receive several prompts, you finally gain access to the server. However, you may receive more prompts during the session.



CAUSE
This behavior occurs because the system registry may be missing one or more values in the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\ClientProtocols

The following values are the core required values for Windows XP or Windows 2000:

The following values are the core required values for Windows 98:

Following the system's protocol binding order, you receive a prompt for credentials on each missing value until a value that matches the next protocol in the binding order is reached.



RESOLUTION
Use one of the following methods to resolve this behavior.

Method 1
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.

Import a valid registry key from a computer that is working correctly. To do this:  Start Registry Editor (Regedt32.exe). Locate and then click the following key in the registry:

KEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\ClientProtocols

 Click the ClientProtocols key. On the File menu, click Export. Save the file with a .reg or a .txt extension in the event you need to send the file by using Outlook. You must save and rename the attachment to a .reg extension to import the key. Quit Registry Editor.</li> Rename the file that you just exported from a .txt file extension to a .reg extension, and then copy it to a folder on your computer.</li> Start Registry Editor (Regedt32.exe).</li> Locate and then click the following key in the registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\ClientProtocols

</li> Select the ClientProtocols folder, click File, and then click Import.</li> Select the .reg file that you saved, and then click Open.</li> Quit Registry Editor.</li> Quit and then restart Outlook 2002.</li></ol>

Method 2
Use Registry Editor to manually create the missing values. To do this: <ol> Start Registry Editor (Regedt32.exe).</li> Locate and then click the following key in the registry:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Rpc\ClientProtocols

</li> Click Edit, click New, and then click String Value.</li> Edit the new string value with the name and data information that is in the table in the &quot;Cause&quot; section of this article.</li> Repeat steps 3 and 4 for each missing value.</li> Quit Registry Editor.</li></ol>

Additional query words: OL2007

Keywords: kbregistry kbpermissions kberrmsg kbprb KB321652

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