Removing False Invaders

I explained what the icons were--but I did not explain how to get rid of them. I thought about it, but I had spent several days on that post and it was time to get it online. When I publish a post, I usually mention it on Twitter. As I was getting ready to write, this message came up in my Twitter Stream:

What a coincidence! I tweeted this back:

Several hours later, I got this reply back:

His next message was:

Although I had been able to remove the icons from my sidebar, I had not documented the process, so the answer had to wait until I had time to get down to some serious work!

First, I had to get the icons to re-appear in the sidebar of my MacBook Pro. To do that I had to plug in an Ethernet cable to the iMac:

The funny icon was back in the side bar of the Finder windows on my MacBook Pro:

Now, to get rid of it! I disconnected the Ethernet cable.

The icon was not removed from my sidebar:

I opened System Preferences > File Sharing. Then I removed the checks beside Screen Sharing, File Sharing and Printer Sharing.

Ah, now we are getting somewhere! While my iMac has disappeared, so has the strange icon:

If this was going to work, I should be able to turn File Sharing back on and the strange icon should not reappear:

Let’s check:

Success!

Let’s do a quick review:

• When File Sharing is begun on a computer, other Macs on the network will see it in the Sharing area of their sidebar.
• If there is only one network connection, the Mac will show a “normal” icon.
• If an Ethernet cable is used for sharing files while AirPort file sharing is enabled, a second icon with the MAC address of the CPU will appear.
• Once that icon has appeared, there is no way to turn it off (make it disappear) unless you disable file sharing. At that point it will disappear.
• If you later connect an Ethernet cable, the icon will reappear and you will need to turn off File Sharing again to make it disappear