Periodically seeing the ASP.NET error CS0656: Missing compiler required member

Question

I'm seeing the following error crop up occasionally (seemingly at random) on my web application. We are running Windows Server 2008R2, IIS 7.5, MVC3, .NET 4.5.

It's the same error every time: CS0656: Missing compiler required member 'Microsoft.CSharp.RuntimeBinder.Binder.BinaryOperation'

When this error occurs, it can take anything from a restart of the application pool, to the re-install of our application itself, to fix it.

The error occurs on brand-new VM images (no previous installation of our software), as well as machines that have previously had our software installed on it. The error can occur upon the first run of the application, or when the application has sat long enough for the IIS application pool to recycle the worker process (so it seems).

This is becoming really difficult to deal with, as I've done a ton of research on this error, and tried multiple solutions, with no luck. Also, the random frequency at which the error occurs has made it very hard to troubleshoot. Any insight into this issue, or ideas on possible solutions, would be greatly appreciated. I'm willing to try almost anything at this point.

Answer 1

This looks familiar. If I recall corectly I had to delete the bin directory and rebuild because older versions of dlls were floating around and this class was introduced in .net 4.0

After some research, this site seems to agree: http://our.umbraco.org/forum/using/ui-questions/20474-Missing-compiler-required-member-MicrosoftCSharpRuntimeBinderBinderInvokeMember