Hi,
DO THIS FIRST
a) Try to do a storage vMotion of that VM and delete the file which are left behind along with the VM folder (if any )
b) Take a VMware snapshot and after completion , Go for DELETE ALL --> This will update the snapshot records in the VMX file and snapshot configuration file with latest number which is unique while taking the snapshot as per the process.
DO THIS AFTERWARDS
a) STOP and set to manual service for Volume shadow copy ,VMware snapshot provider and Virtual Disk inside the Guest OS. Wait and Check for schedule backup.