This should not be happening. Outlook addin can't find assembly reference?? Why?

I can not work this out. I have a class library called 'ABC.Service'. In this class library I have referenced other projects from my solution.

In my 'ABC.Service' I have consistently named my classes namespace 'ABC.Service'.

I have made a project reference to this 'ABC.Service' and another class library called 'ABC.Entities' from a OutlookAddin project in the same solution.

For some reason the outlook addin project does not compile and outputs that 'The type or name 'Service' does not exist in the namespace 'ABC' (are you missing an assembly reference?) . However it does not complain about the 'ABC.Entities' classes???

The 'ABC.Service' compiles just fine and can be referenced successfully from a Windows project in the same solution which compiles just fine.

In the outlook addin intellisense can detect the namespace and class just fine also

I am obviously not missing the reference so the error message is so misleading.

I have tried;

• Cleaning project/solution
• Shutting down VS2010
• Restarting Computer

I can only see 2 possible problems (which I can not understand why they would be problems)

• In the 'ABC.Service' I have a reference to 'Micorosoft.Office.Interop.Word' assembly.Could this be doing something?
• I have some generated code with a namespace called 'ABC.BusinessLogic' instead of 'ABC.Service' - removing this generated code to see if this is the problem would be a nightmare as much more would need to be changed to get it to compile and I really don't understand why it would be a problem

Has a开发者_运维技巧nyone got any ideas??

Any help appreciated

I've heard of this sort of thing happening when a project's build mode gets changed to "Client Profile." You might want to check on that.