How do I forget a wireless network on my Mac?

Even if you "forget" a network, AirPort will still automatically connect to a secured network if it finds the key in the Keychain if a preferred network is temporarily unavailable. So make sure you remember to remove the key from the Keychain if you don't want to switch over to an "old" network if your new one temporarily goes down.

Thank you so much for this clear explanation and solution! There's an unprotected network near my house which kept coming up first. I didn't want to get rid of it forever (in case our system goes down!), and I'd never noticed the priority moving.

I'll remember to come to you first from now on.

thanks for information on this worked fine

Thanks so much! I was using my neighbour's network for a couple weeks after I'd just moved in, and it'll be nice not to have to switch away from it every time I open my laptop! Site bookmarked.

Thanks Dave. It's always a pleasure to see your site ranked 1 on google for an answer I'm looking for.

Thank you soo much! I don't understand why that's an "Advanced" setting.

Fantastic! Seeing my neighbor's linksys had been driving me batty... it was unsecured for years and I inadvertently found myself using their router for browsing!

What a joke! If I were unethical, I could have canceled our internet service and just used theirs! No wonder that strange car keeps parking near their house and the driver has a laptop! :-)

So, with this tip, I no longer see linksys, nor will my MacBook Pro log onto to theirs when our router is turned off (we turn it off nightly).

Worked Perfect!!!! If one of the screens are locked make sure you click the small lock on the corner of the window. You just helped me out so much, thanks a lot!!