I have followed various procedures found in other discussions, specifically using VSSADMIN to resize shadow copy storage (unbounded) and running a batch file provided by one of the experts. Neither worked.
Drive 0 contains the C: drive (1848 GB), an EFI System partition (500 MB), an OEM partition (40MB), a Recovery partition (500 MB), and a Recovery partition (13.98 GB).
I edited the backup job several times and sort of lost track of what the default backup contained and feel I need to educate myself further on what needs backing up. In any event it apopears that the VSS errors were related to some partition or partitions other than c: as once I whittled the backup down to only C: it ran fine.
I don't know how to go about allocating shadow storage for other partitions that should be backed up and this is where I need the advice. In other words VSSADMIN asks for a <ForVolumeSpec> and I'm not sure how to do that.
By the way, the backup I just ran went very quickly. Compared to other products I've seen I am very encouraged by this.