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Instead of trying to undo an update, try working with the situation. First, on the MacBook turn off Airport, you can do this by going to the Menu Bar, click the Airport icon and click: Turn Airport Off
Now, shut down your MacBook. Disable any peripherals, like USB ports, Ethernet, everything. If you have a cable modem, turn it off or unplug it. Now, boot the MacBook, turn your cable modem back on, let it recycle, can takes a few minutes. Now turn on Airport from the Menu Bar and see if Airport is functioning as it should.
If not, try this: Launch Disk Utility, (Applications/Utilities) and Repair Disk Permissions. Select MacintoshHD 10.x.x in the panel on the left, select the FirstAid tab, then click: Repair Disk Permissions. Quit DU when it's finished and reboot. See if Airport is working.
I agree with Nerowolfe, I do not think there's anyway to UNdo this update other than doing an Archive and Install, but trouble shooting will probably take less time.
Carolyn 🙂
Message was edited by: Carolyn Samit