This is a known issue affecting VMware NSX for vSphere 6.x and ESXi 5.x/6.0 hosts.
Currently, there is no resolution.
To work around this issue, free the additional space on the bootbank by un-installing non-required VIBs on the ESXi host using the
esxcli software vib remove -n vib-name command. For more information, see the
Remove VIBs from a Host section in the
vSphere Upgrade Guide.
For confirmation to remove non-required VIBs from the ESXi host, contact your hardware vendor.