Sometimes we need to provide the public key token in the config file, like this. Dotnetthoughts.Utilities, Version=1.2.0.1, Culture=neutral, PublicKeyToken=a78a5c561934e012 You can find the public key token using Strong Name tool(sn.exe). Open your Visual Studio 2010 command prompt, use the following command. (sn.exe will be also available in C:\Program Files\Microsoft SDKs\Windows\[Version]\bin location) This will print the [...]