At work we’ve recently upgraded from Visual Studio 2005 to 2008, and are now upgrading to Visual Studio 2010. Being the (willful) guinea pig of the bunch, I have been the first one onto 2010. In upgrading a large portion of our main project, I discovered something interesting had happened in the upgrade. When I attempted the first build on Visual Studio 2010, I got a horrendous number of errors – in the thousands!
After a bit of digging I had discovered that each project within the solution was targeting the .Net 2.0 framework rather than the .Net 3.0 framework as they previously had been. This was causing a bunch of references (namely System.Runtime.Serialization and System.ServiceModel) to go missing and not be included, which caused absolute havoc.
After switching all the projects back over to be built for .Net 3.0, things seem to be working.
So, if you are encountering issues when upgrading from Visual Studio 2008 to Visual Studio 2010, and you are getting tons of errors, be sure to check your project references to see if they are valid as well as what version each project is building against.
I do have to say, the first time I saw the Visual Studio 2010 IDE, I wasn’t particularly thrilled, but it is starting to grow on me. I really do wonder how they come up with the color schemes and styles that they do at Microsoft…