Question: I have a Visual Studio 2010 solution with a few projects. I can successfully build with Build -> Build Solution or Build -> Build MyCompany.MyProduct.MyProject. After building I press CTRL+F5 and successfully run the start up project. This works as expected.

After I change a source file, save it and then again build (with either Build -> Build Solution or Build -> Build MyCompany.MyProduct.MyProject) it builds successfully. I am still able to press CTRL+F5 and run the startup project. This again works as expected.

The problem is in the following scenario:
After I change a source file, save it and directly press CTRL+F5 then Visual Studio 2010 says BUILD FAILED and there are no errors. And it doesn't start my startup project (of course).

Am I missing something?

Answer: 
Close Visual Studio, delete the `.suo` file for your solution. It's a 'hidden file' in Windows and contains user preferences, but it can also do nasty things.
if your solution contains too many projects , 

build projects individually, 

Check which project is failing 

for that project check the references of that project , if on any reference if their is yellow color mark, then delete that reference , and add that again , then build and check,

this will work 

or 

check in output window , each line , in some line it may be showing , dependency is their , but didnt found it , that is the problem causing 

this may be due to file corruption