What filesystem is your new My Book formatted as? NTFS or exFAT.
If it’s exFAT, which I believe is the factory shipped filesystem, then you’re likely being limited to 12 characters, where NTFS can support more.
Try formatting (or reformatting) your new My Book through Windows Explorer or Disk Management as NTFS and see if you can exceed the 12 character limit. NOTE: All existing data on the drive will be erased!
