Could not find add method: AddPrefetch (type: System.String)

 Issue:

After the initial unicorn setup with Sitecore instance, there may be a chance to get below issue

Could not find add method: AddPrefetch (type: System.String)

and there is no more information into log files. 



Fix:

To resolve this issue, 

ensure ranbow.*.dll, unicorn.*.dll, configy.dll and Kamsar.WebConsole.dll properly deployed in wwwroot/instancename/bin directory.