When trying to access a SharePoint 2007 or SharePoint 2010 site on the same machines that it is installed on you may be continuously prompted for your credentials – even if you are the Site Collection Administrator for the site collection that the site resides in. This is most likely caused by Loopback Checking which is enabled on Windows 2003 and Windows 2008. The purpose of Loopback Checking and steps on how to disable it are detailed in the Technet article ‘You receive error 401.1 when you browse a Web site that uses Integrated Authentication and is hosted on IIS 5.1 or a later version‘.
The following steps briefly illustrate how to disable Loopback Checking:
- Click Start->Run and then type regedit and click OK.
- Navigate to the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa.
- Right-click Lsa and select New->DWORD Value.
- Type DisableLoopbackCheck and hit Enter.
- Right-click DisableLoopbackCheck and the click Modify.
- Type 1 into the Value data box and click OK.
- Close regedit and reboot your computer.
It is important to note that this is not Microsoft’s preferred approach but it is the simplest and shouldn’t be too much of a worry on a development machine.
