To get this share working, in ex. when you need another server to install a service on this (in my example it was Veeam proxy installation), you need to add this registry key:
DWORD 32bit: LocalAccountTokenFilterPolicy
Set this to: 1
Why I’m running workgroup with Veeam Proxy?
Simple! – To protect my backups again ransomeware like Cryptolocker 🙂