Yesterday I was trying to add a database to the App_Data folder of a simple web application I was creating. During one of my computer re-installs, I didn't install SQL Express since I normally use a full blown SQL instance, so I really had no need for it. Now that I did need it, I wanted to run SQL Express 2008. I am running Windows Vista x64, so I proceeded to download SQL Express 2008 x64. I installed it and loaded up SQL Server Management Studio to make sure the instance was working (I just used the default of SQLEXPRESS for the instance name). Everything was fine. I then fired up Visual Studio, right-clicked on the App_Data folder of the web app, and... error (Figure 1).
Figure 1 - Connections to SQL require SQL Express
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