An across-the-board password change wreaks havoc with cached wireless passwords. I had no issue with a stock Macbook Air – I deleted the wireless network and then reconnected to the private locked network entering a username and password.
My company Macbook wouldn't show or allow me to delete the network and therefore I couldn't delete the cached password without delving deeper.
I went deeper into the OSX realm.
There is a place where wireless passwords are stored and you can directly delete them…
Open "Finder." In your Finder window, navigate to the "Applications" folder and then into the "Utilities Folder." After you've opened the Utilities Folder, find "Keychain Access."
Double-click on "Keychain Access." When the program opens, you will see a window divided into three panes. Before proceeding, click "Login" in the Keychains pane at the top left. Immediately below, in the "Category" pane, click "All Items."
Scroll through the list of saved passwords on the right. If you have a large number of passwords, you can sort them according to name or kind to make the list easier to navigate. To resort the list, click on "Name" to sort alphabetically or "Kind" to sort by type of password. When you've located the name of the wireless network password you wish to delete, click on that name once to highlight that keychain entry.
Press the "Delete" key on your keyboard. A dialog will pop up asking you to confirm that you want to delete the keychain. Make sure you have selected the correct keychain entry, because you cannot recover deleted keychain password entries. When you have confirmed the proper entry, click "Delete" to remove the wireless password you selected.
Read more: How Do I Delete a Wireless Password for Apple Mac? | eHow.com http://www.ehow.com/how_6868140_do-wireless-password-apple-mac_.html#ixzz1zs9y0eSB
Very cool…
Since I did this though, the wireless insists on logging me into the public version fo the wireless (useless to work with internal servers). Every morning I manually move to the private version of the wireless.
—doug