You can find out what is causing Visual Studio to think each project is out of date, and then address the issue directly.
- Select Tools → Options → Projects and Solutions → Build and Run.
- For the setting "MSBuild project build output verbosity:" select "Diagnostic".
- Build.
You will get a huge amount of output in the output window detailing exactly what the build is doing. Before building each project it will print out why it thinks it is out of date. An example of such output is:
Project 'Foo' is not up to date. Input file 'c:\Bar.cs' is modified after output file
These "not up to date" messages should point you to the real cause of the unnecessary builds, which you can then fix.
