And all it takes is checking a checkbox, just one checkbox!

That’s the solution to a problem with which I’ve been struggling yesterday.  What problem?  Let me tell you.

I’ve been installing Master Data Services (MDS) on my SQL Server 2008 R2.  This feature will not only create a database but also a website which you can use to manage MDS.  And it’s the website part that I had a problem with.  Everything installed just fine but when I tried to load the site in Internet Explorer 8 on my Windows 7 64-bit machine, I got the following error:

HTTP Error 401.2 – Unauthorized

You are not authorized to view this page due to invalid authentication headers.

Great, an authentication problem – aren’t those our favorite ones?  And like any decent developer, I didn’t waste my time reading all the text on the error page and started investigating the issue.  I had a look at the settings of the Application Pool and those of the Default Web Site.  I also tried changing the security settings in IE.  At the end I think I have tried every possible setting in IIS 7.5 (which is the version that ships with Windows 7), but I kept getting that same error.

I let some time pass (not on purpose but because we were going to visit my parents-in-law) and in the evening I decided to have another look.  This time I took the effort of reading everything mentioned in the error:

Do you see that blue link down at the bottom, which I’ve marked with a red rectangle?  That’s where I got the answer from!  Clicking it opened up the following Microsoft Support page: Error message when you try to visit a Web page that is hosted on IIS 7.0: "HTTP Error 401.2 – Unauthorized".

Sounds familiar doesn’t it?  Okay, it’s meant for IIS 7.0 but works for 7.5 as well.

I solved my problem by applying Resolution 1.  In short: IIS was running without the Windows Authentication module installed!  Apparently that is not installed by default when you activate Internet Information Services through the “Turn Windows features on or off” window.  Here’s a screenshot showing what needs to be added:

Once that was set up I was able to load the MDS application:

If you’re looking for instructions on how to install and configure Master Data Services, have a look at this article at the Master Data Services Team blog.

(Do I need to mention that this was the first-ever web application that I tried running on Windows 7? )

Have fun!

Valentino.