We have a problem with opening Office documents where some users get a login dialog and others don't. If the user press Cancel the dialog disappears and the document is opened properly. If the enter their credentials they are usually prompted the same dialog again (until they press Cancel).

All computers have the site in their Intranet-zone and they all have IE8. I believe the error is related to settings (registry?) on the computers as the same user can use another one without getting the dialog. The error exists mainly on machines running Windows 7. At least one tested on Windows 7 where it didn't work and then in Vista where it worked as expected (no dialog).

I have found a kb-article which I think can be related (http://support.microsoft.com/?id=943280) but as far as I understand I should have the error in Vista as well. I have been unable to test the solution (editing the registry).

Any suggestions?

Regards, Adrian.

3 Answers 3


Do you have Kernel Mode Authentication enabled on your IIS site for your SharePoint web application? This is normally off for SharePoint sites but can be on as a result of an upgrade for example.

Useful link on this problem:


You can also continue to use Kernel Mode Authentication on the 2007 version of SharePoint by configuring it to use the application pool credentials. The suggested approach is to use the useAppPoolCredentials attribute of the windowsAuthentication element in the applicationHost.config file.

More details on Spence Harbar's site. Remember that this fix won't work on SharePoint 2010 (it uses a newer authentication protocol), only 2007. On SharePoint 2010 you will still need to disable KMA for your content web applications.

  • We do indeed! I will try to get it unchecked and come back with the results. Forgot to mention that the site is MOSS 2007.
    – Adrian
    Commented Apr 3, 2011 at 20:39
  • To clarify, Kernel Mode Authentication is disabled by default for web apps created in SharePoint 2010. This wasn't the case for SharePoint 2007.
    – SPDoctor
    Commented Apr 4, 2011 at 8:45
  • And unfortunately, disabling it made the site inaccessible
    – Adrian
    Commented Apr 7, 2011 at 8:49
  • Should still work but may need work on configuration. A better fix is to configure KMA to use the app pool credentials - I will update answer with more details.
    – SPDoctor
    Commented Apr 7, 2011 at 9:19

I think this issue might have something to do with WebDAV protocol for opening office documents. Here the relevant knowledge-base article:

SharePoint 2007 or 2010: Office Documents open ReadOnly from SharePoint site

IE8 will try a few different methods to open the documents and the WebDAV method has issues with Windows 7.


Figured this one out after about 2-3 hours of troubleshooting. Make sure they have read access to the parent site where the document library is stored. If they only have "Limited Access" is issue occurs, though cancelling thru the log-in screens it will give them the file. - SharePoint 2010 / Office 2010.

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