Either the assembly has no strong name, an invalid one, or the strong name is valid only because of the computer configuration. ...

Either the assembly has no strong name, an invalid one, or the strong name is valid only because of the computer configuration. The assembly should not be deployed in this state. The most common causes of this are: 1) The assembly's contents were modified after it was signed. 2) The signing process failed. 3) The assembly was delay-signed. 4) A registry key existed that allowed the check to pass (where it would not have otherwise).