Referenced Project gets lost at Compile Time in VS 2008

Question

I know the same tag line has been used to answer a same type of question, but, the answers there didnt help. My solutions has a couple of projects in them. One project say Prj.Infrastructure has some interfaces IA, IB, IC, ID and IE which are implemented by some C++/CLI class in the project Prj.Bridge and also used in some winforms in Prj.UI.

When I build each project separately, it builds fine, But when I build the whole solution, It loses interfaces IA, IB and IC for some reason and the Prj.UI cant find it giving an error like

Error 6 The type or namespace name 'IA' could not be found (are you missing a using directive or an assembly reference?) D:\svnroot\branches\blah1\blah2\blah3\blah4\blah5\blah6\INVS.cs

Where INVS was implementing IA.

I have tried the following : I have cleaned and built already for loads of times. I checked all the projects in my solution and the client profile check box is unchecked. Removed Resharper (since Resharper had no trouble recognizing the referenced project, I thought it might be worth a shot) Removed and re-added the reference and using statement. Also tried checking out my branch on other computer and it still failed.

Please help me in this, I have been stuck for 2 days now.

Edit: Its for .Net 3.5

Answer 1

solution->properties

common properties->project dependencies

Prj.UI depends on Prj.Infrastructure

Answer 2

Sorry everyone. It turns out my colleague had added a registry in the build script (Added key under HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft.NETFramework\AssemblyFolders) Pointing to another build folder (from another source control checkout), So whenever I was building the whole solution, It was getting the data from that and was not recognising the new added interfaces. Sorry for the problem, It turns out, we may add one more possibility for this problem. Check your registries because thats where Visual Studio gets its build information while building the whole solution. VS uses this folder to resolves references (ie, shipping APIs). It was resolving a library from this folder and not the branch output folder, its how you add asssemblies into the Add References section