I have two core switches with between 50 and 100 ports each configured for end users. I have port security enabled on all of these ports. 3 of these ports in unrelated locations will almost immediately errdisable when portsecurity is turned on but are fine otherwise. I have sticky MAC addresses on and have repeatedly reset the ports and the MAC addresses associated with them to no effect. There is only one device connected to each port, a zero client. The running configuration is identical to other working ports. Is this a connection issue?
do you use any other security feature like dhcp snooping or dot1x?
with show port-security <interface> you get an output for securing-down the port.
also you can try debug port-security and provoke the error. then you can show me the output and I can help you.
I guess you use dot1x or not?