Posting this to start a discussion from a Packer group discussion
[[WSMAN ERROR CODE: 5]: <f:WSManFault Code='5' Machine='127.0.0.1' xmlns:f='http://schemas.microsoft.com/wbem/wsman/1/wsmanfault'><f:Message><f:ProviderFault path='%systemroot%\system32\winrscmd.dll' provider='Shell cmd plugin'>Access is denied. </f:ProviderFault></f:Message></f:WSManFault>]
I've seen this error reproduced outside this codebase via test-kitchen which is Ruby based, so its not necessarily a winrmcp lib problem. The common denominator seems to be uploading files to a Windows 2012R2 guest via WinRM from a Linux host. Oddly this seems to work fine from an OS X host.