For ESXi 6.0 VM's the recommendation is to use vmxnet3 virtual network adapters.
Please check the VM's configuration (.vmx) file and add/edit the following line for each network adapter:
ethernet#.virtualDev = "vmxnet3"
(where # represents the adapter's number)
Make sure you do this with either VMware Workstation, or at least the VM's tab closed to ensure the configuration is re-read after the manual modification.
André