Your Mac will try to connect to the Internet according to the order in which your services are listed in your Network system preference.
I have a MacBook Pro, and I recently bought a wireless modem so that I can use the Internet when I’m away from my DSL line. After using my wireless modem for the first time, I disconnected it and put it away. Since then, a window keeps popping up that says “Internet Connect. The selected communication device does not exist. Please verify your settings and try again.” How can I make it go away?
Whenever your Mac uses the Internet, it needs to know which network service to use to establish a connection. A network service is a group of settings for a specific network port, which is a physical piece of networking hardware, such as your wireless modem, your Ethernet port, or your AirPort card. Your Mac will try to connect to the Internet in the order that these services are listed in System Preferences > Network. If your wireless modem is listed first, that’s the first port on which your Mac will try to establish an Internet connection, and since the wireless modem isn’t available, you get that error message.
To change the order, go to System Preferences > Network, click the Actions button (it looks like a tiny gear) and choose Set Service Order. Drag the services into the order that you prefer your Mac to use—you want your wireless modem to be lower on the list, so that your Mac won’t attempt to use it unless the previous methods are unavailable.
Another solution is to keep the wireless modem at the top of the service order list, but let your Mac know that you prefer to connect manually with your wireless modem instead of automatically. To do this, go to System Preferences > Network, and click your wireless modem in the left-hand column. Then click the Advanced button and choose the PPP tab. Uncheck the checkbox that says Connect Automatically When Needed, click OK, then Apply.
From then on, you’ll have to manually connect to the Internet when you want to use your wireless modem, which you can do by clicking on the Connect button that appears in System Preferences > Network when you choose your wireless modem in the left-hand column. Or, check the box for Show Modem Status In Menubar, which will give you a telephone icon in your menubar that you can click and choose Connect.
