Problem in accessing a project from another in same solution in Visual Studio

I have a windows service project which I added to a few other projects. I added the references and I can access them. Then when I build, it says "Does not exist" Then I remove the reference and add it again and I can access it, but still fails when I build and can't access it later. Any clue wh开发者_运维技巧at does this happen form?

A few things to check:

Where does your web service get built to? You might like to check its not getting deployed to a \bin folder that has its contents deleted on a rebuild.

Is it added as a web reference or as a reference directly to an assembly?