I just got this message "This computer's local hostname 'firstname-lastname-iMac.local' is already in use on this network. The name has been changed to 'firstname-lastname-iMac-2.local'."
what does this mean?
Is this a security issue?
This is normal. You cannot have two macs with the same hostname in the network. The hostname is the name that your mac is recognized in a network.
Sometimes this message means that you have two simultaneous connections to the same local network: probably Ethernet and Wi-Fi. Disconnect the Ethernet cable or turn off Wi-Fi.
Sometimes it happens because a device that gets its network address from the router wakes from sleep, and the address it was using before has been assigned to another device.
Rename the computer in the Sharing preference pane.
But I only have one mac. The only other computer connected to the internet is my pc laptop.
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