If device is added through one of the configuration interfaces, verify that the device configuration file, /etc/sysconfig/network-scripts/ifcfg-<dev> is not already present.
If the device is edited through one of the configuration interfaces, verify that the device configuration file, /etc/sysconfig/network-scripts/ifcfg-<dev> is present and is not RCS locked.
To determine the cause, look for errors in following files:
Recovery: