System.NotSupportedException: An attempt was made to load an assembly from a network location which would have caused the assembly to be sandboxed in previous versions of the .NET Framework while registering plugin in CRM 2011

Hi,

One of my colleagues was getting the above error while trying to register the plugin using plugin registration tool. This was because the plugin was copied from a network location and hence blocked. Right clicking the plugin assembly, selecting properties and then selecting unblock in the Security section of the General tab resolved the issue.

http://blogs.msdn.com/b/drew/archive/2009/12/24/xunit-and-td-net-fixing-the-attempt-was-made-to-load-an-assembly-from-a-network-location-problem.aspx

Hope it helps.