DLL reference error

Hi,
I have a solution containing many projects. Once the solution is built, the compiled dll is copied to a common location. In the solution, I have a project (A), for which I have referred a dll(M.dll) from the same common location. I have other projects(B,C,D, ...) which in turn has a reference to the project A. The issue is that when I removed the M.dll reference from project A and the M.dll from common location, compiling the solution still copies the M.dll to the common location.
Please advise. Thanks in advance.