Server was moved and domain contraller not available any more. Is it a way to disjoin Domain on Win 2008 R2 Core Installation Hyper-V?
Is the server a Domain Controller? If not, I believe you can just put the server in workgroup mode and delete the computer account from the domain. Someone correct me if I'm missing something here.
You should of course be aware of the excellent core utilities which makes all this a bit simpler for us command line impaired.
I was dealing with this exact issue when trying to disconnect a copied VM from another network. The DC from the previous environment wasn't available in the new location and my VM was also a Win2008R2 Core installation. Under the same conditions, the GUI domain/workgroup tools in Computer Properties would have disconnected it from the domain.
I was using the domain GUI tool from CoreConfig and got this error, and also got it from netdom. Adding in the /force option in netdom was the fix. The GUI tools from a full installation of Windows apparently take care of this automatically.
netdom remove /d:mydomain mywksta /ud:mydomain\admin /pd:password /force