In .Net framework 2.0, we will cache assembly loading failures. (See http://blogs.msdn.com/junfeng/archive/2004/07/22/190813.aspx for more detail.)

Not everyone like the decision. To opt out this, add the following snippet to your app.config file.

<configuration>

            <runtime>

                        <disableCachingBindingFailures enabled="1" />

            </runtime>

</configuration>