An administrator is trying to add a new virtual disk of 3TB to a virtual machine on a recently upgraded ESXi 6.x host, but receives this error: The disk capacity entered was not a properly formed numb

Upgrading the VMFS datastore version alone does not modify the block size setting that controls the maximum virtual disk file size.

VMFS3 datastores use block size to determine the maximum supported virtual disk file size - an 8MB block size supports virtual disks up to 2TB, which is required to accommodate the requested 3TB disk. Without changing the block size, the datastore cannot accept the large virtual disk creation request, resulting in the 'out of range' error.

Moving the virtual machine to a datastore with more free space does not address the block size limitation that causes the capacity validation error.

vmkfstools is a CLI utility for virtual disk management tasks; upgrading a datastore to VMFS6 is done through vCenter or esxcli, not vmkfstools.