This issue can occur when too many ports are configured on the vSphere Standard Switches. For more information, see
Networking Maximums in the
Configuration Maximums guide. The number of ports on a vSwitch can be modified at any time but the changes do not take effect until the ESXi server is restarted. If the number of ports exceeds the configuration maximum, a vSwitch can disappear from vCenter Server after a reboot of the ESXi server. Details of the missing vSwitch are still listed in the
esx.conf file (located in
/etc/vmware/) but the vSwitch is not visible in the vSphere Client.