Unable to create VM template

Hi Folks,

I am trying to create a VM template from an existing VM on the host machine.  I keep getting an error (2903)  VMM could not locate the file/folder \\...\VMMLibrary\..\VMxyz.vhdx on the abc server.     The system cannot find the specified file.     

The VM was created in Hyper-V on server 2012 R2 and is a generate 1 VM using a VHD  (its just a simple VM with 4gb memory and a 60GB disk).  I'm not sure why there is a reference to a VHDX.

Its SCVMM 2012 R2.

Does anyone have an idea what the real issue might be?

Regards

Andy