Make sure the target of your main project is set to x86 and not 'All Processors'. ADODB Interop requires 32 bit operation so if you compile with neutral it will potentially run in 64 bit and break - the compiler is letting you know that this is a problem.
Why are you using ADODB and CDO? These have much better replacements in .NET.
+++ Rick ---
>With 2012, I have four warnings in my project. They are similar to this one:
>
>There was a mismatch between the processor architecture of the project being built "MSIL" and the processor architecture of the reference "Interop.ADODB, Version=6.0.0.0, Culture=neutral, processorArchitecture=x86", "x86". This mismatch may cause runtime failures. Please consider changing the targeted processor architecture of your project through the Configuration Manager so as to align the processor architectures between your project and references, or take a dependency on references with a processor architecture that matches the targeted processor architecture of your project.
>
>The four files are:
>
>Interop.ADODB
>Interop.CDO
>Interop.Scripting
>Interop.Shell32
>
>Is there anything that superceeds that in .NET Framework 4.5? Is this warning something to not worry about at this point? Anyone would know why 2012 gives warnings where 2010 wasn't?
