我最近开始在.NET 4.5 MVC-Application中出现以下错误：
Could not load file or assembly 'EntityFramework' or one of its dependencies. Strong name signature could not be verified. The assembly may have been tampered with, or it was delay signed but not fully signed with the correct private key. (Exception from HRESULT: 0x80131045)
这怎么可能发生？我已经检查了EntityFramework.dll的有效性（使用sn.exe -v）并使用NuGet数据包管理器重新下载它......但仍无济于事。
我怎样才能克服这个？