DLL linking error from addin

[Rana S]

I currently have a legacy addin, which used DLL built in .NET 3.5 and interacts with + win32  DLL written in C++.

I had to upgrade the .NET to 4.5.2 and C++ dll started giving Mixed mode assembly error. So I recompiled C++ as well.

Now when I run the addin, it gives DLL linking error. 32 bit Excel is installed on 64 bit machine, all my .NET projects are built with platform target = x86, C++ is WIN32,  Addin project is set to Any CPU. When I run the code outside of addin (in its own exe) it works.

Any ideas on what am I doing wrong?