Creating Ad-Hoc networks on older MacBooks can be a pain. Here’s a nice solution:
~ Open System Profiler and click on Airport in the list.
~ Note your Airport device and vendor ID, something like:
Card Type: AirPort Extreme (0x168c, 0x87)
Firmware Version: Atheros 5416: 220.127.116.11
~ What we want is 0x168c and 0x87.
~ Open Terminal
~ Type ‘sudo nano /System/Library/Extensions/IO80211Family.kext/Contents/PlugIns/AirPortAtheros.kext/Contents/Info.plist’ and hit enter
~ Try to find these lines:
~ Just before the , add another line:
~ 168c and 87 are the IDs I got from my System Profiler. Yours may be different and you should use the ones you get.
~ Finally, you should have:
~ Exit nano (Ctrl+X, Y to save, Enter)
~ Type (in Terminal) ‘sudo touch /System/Library/Extensions’
~ Reboot your system (will take a while to generate the kext cache again)
~ Check if you can create the Computer-to-Computer network. If not, try turning airport off and back on again.