Solution to the "device em1 does not seem to be present delaying initialization" error

If you get the "device em1 does not seem to be present delaying initialization" error when you start the network service in Centos 6, your MAC address may not match or is not visible.

Open em1's configuration file and check the HWADDR and UUID. If it's in a comment line, remove it.

nano /etc/sysconfig/network-scripts/ifcfg-em1

We remove the /etc/udev/rules.d/70-persistent-net.rules file and restart the server.

rm /etc/udev/rules.d/70-persistent-net.rules

reboot