"The located assembly's manifest definition with name 'MyRootNamespace.MyNamespace' does not match the assembly reference."

"The located assembly's manifest definition with name 'MyRootNamespace.MyNamespace' does not match the assembly reference."

Ahhhh, this one is a joy, isn't it? Just when you think everything is working out fine - your latest dll error-free and nicely compiled, then bam - this lovely little son-of-a-gun comes along.

The error is caused by the assembly reference within your project being 'out of synch' with the assembly itself - i.e. there exists a reference to a different version of the assembly, be it older or newer. This can occur more commonly when you're throwing around new versions of a dll between projects and you forget to update the appropriate assembly reference info.

What to do if this happens? Well, if using VS IDE, simply re-saving should solve it, however if it doesn't, right click the reference under the 'References' folder, select 'Remove' and then add it back in again.