Visual Studio error when trying to open dbproj files

I have Visual Studio 2008 Database Edition, and everything worked great until the first time I tried to load a .dbproj file. These database project files work for the other developers I work with, but when I try to open it, I just get an error message "Object reference ot set to an instance of an object."

It's probably the same problem this guy is having, although he didn't do a good job of describing it and has no solution.

Every other kind of project file开发者_JAVA技巧 loads and builds and runs normally. dbproj files all generate this cryptic error. I just tried a fresh removal and reinstall of Visual Studio 2008 DE to no avail. Could this have something to do with my SQL 2005 installation? (This also works normally through SQL Server Management Studio.)

** UPDATE **

Probably even more importantly, this same error occurs when I try to make a new dbproj file. Every other type of project can be created no problem.

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You need to tell Visual Studio the correct instance of SQL Server to use for validation.

Tools>Options>DatabaseTools

Change the settings in "Data Connections" and "Design-time Validation Database" to reflect the correct instance.

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After many failed re-configurations and re-installations, a member of my team discovered the problem!

Under Tools > Options > Database Tools > Design-time Validation Database, there is an option to set your SQL Server Instance Name. Visual Studio automatically picks this when it's installed.

The key is that Visual Studio doesn't necessarily pick the right one. I happen to have 3 SQL server instances on my machine. SQLEXPRESS (a 2005 instance that Visual Studio installed alongside itself), SQLEXPRESS2005, a 2005 instance I installed, and SQLEXPRESS2008, which I also installed.

Visual Studio had configured itself to connect to the SQLEXPRESS2008 instance, even though it only supports SQL2005 dbproj files by default. By opening this dialogue, and updating the server instance name, the error no longer appeared and I was able to open dbproj files: