Error during VeeamZip backup attempt: "An error occurred while saving the snapshot: failed to quiesce the virtual machine"
Some of the VMware KB suggestions include:
2069952
2034002
But, the virtual disk service suggestion didn't help, and the other suggestion requires a reboot, which was not possible in my situation.
The solution I found was to modify the VMware tools installation to REMOVE the VMware tools' VSS option.