To reset your expired ESX 4.x, ESXi 4.x, ESXi 5.x or ESXi 6.x 60 day evaluation license:
simply copy the code below and paste it into your SSH session.
rm -r /etc/vmware/license.cfg
cp /etc/vmware/.#license.cfg /etc/vmware/license.cfg
/etc/init.d/vpxa restart