Temporary fix as per Apple Product specialist OSX 10.5.8 WIFI fix

I had a similar problem. After sleeping my MacBook Air after the 10.5.8 update, I would lose my WiFi connection until I stopped and restarted Airport. The fix for me was to run AppleJack, a free utility that does a deep system clean in single user mode. All is well now. HTH.

nice. I might do that today. I am going to the apple store in a few hours. I wonder what they are going to do or could do. Must have been a piece of cake, just restore 2 files and you're good to go.

Yes, it was VERY easy to do. Took about five minutes and everything is working as it should.

This solution Kerry posted while nice, poses another unknown possible difficulty.
I've seen it happen before when mixing old kernel extensions with newer operating systems, that the kernel extensions don't get updated on the next update, and they no longer work, and cause a kernel panic, when you further update. So while it may work nice now, I would be sure the next time you do any operating system installation update, or upgrade to backup your data at least twice, before attempting the upgrade, in case something funny happens to the kernel extensions.

how can this work when the date on these files is older than the update?

the date on mine is february 2008, so the time machine backup is just going to replace them with the same file.

The one which did change with the update is IOPCIFamily.kext so whether restoring that would help I don't know

Changing these two .kext files did not fix my problem. However, I have found alternative solution that work for me 🙂 Probably it worthwhile to share my experience here.

Situation: My MacBook (Unibody, C2D) failed to connect to TimeMachine after I updated it to 10.5.8. Strangely, My another MacBook white (C2D) has no similar problem at all.

Solution: Remove ALL the "preferred networks", restart, set up the network again by key in name and password. Pls find the step by step guide below.
1) Open "System Pref." ; Select "Network".
2)Select "Airport" tab on the right hand side. Click on "Advance..." button.
3)Delete all the profile under "preferred Networks".
4) Restart.
5) Repeat step 1 and 2.
6) set up the Wifi in "preferred Networks" again.

Hi Kerry, your FIX suggestion works with the MBP 2.6 Intel. My other Macs run on OSX 10.5.7. Better not to touch until Apple releases update for the UPDATE. iTunes sync with Apple TV and external Data stored on a Drobo works without crashing when the MBP works on battery. Thanks a million...

Just as a reminder, the product specialist was technically advising a dangerous course of action by suggesting you revert the kext in this manner.

If you find this solves your issue, you should instead revert your entire system back to Mac OS X 10.5.7, either by use of Time Machine or by performing an Archive and Install of Mac OS X and updating the newly installed image only to 10.5.7.

Mixing and matching kext versions can lead to system instability, data corruption and may prevent a fix from installing properly when released.

simon gamble wrote:
how can this work when the date on these files is older than the update?

the date on mine is february 2008, so the time machine backup is just going to replace them with the same file.

The one which did change with the update is IOPCIFamily.kext so whether restoring that would help I don't know

The date on the package is not important, if you "Show Package Contents" on the IO8211Family kext (and any other) you can dig down until you get to AppleAirPortBrcm4311.kext in the plug-ins folder. This, I believe, is the driver and has a date and version number. 10.5.6 has version 3.6.1, 10.5.7 has version 3.6.3 and 10.5.8 has 3.6.5...

Kerry Dawson wrote:
I'm not sure why you're saying this. I've had no trouble nor has my roommate on his machine. In fact, this very fix is now just recently posted at MacFixit - a little more detail. My system is working great since doing this where before it was pathetic.

Just because you're not having issues doesn't mean that problems can't occur, nor that the procedure is safe.

It's kind of like driving at 80 MPH down a 55 MPH freeway - just because you never get ticketed doesn't mean there's not a risk in doing so.

Apple has now published a real fix for this:

About AirPort Client Update for MacBook and MacBook Pro

This update is recommended for some Intel-based Macintosh computers running Mac OS X v10.5.8 and addresses an issue with AirPort performance while running on battery power. It may only be installed on:

MacBook (13-inch, Late 2007)
MacBook (13-inch, Early 2008)
MacBook (13-inch, Late 2008)
MacBook Pro (15-inch, Early 2008)
MacBook Pro (17-inch, Early 2008)
MacBook Pro (17-inch, Late 2008)

http://support.apple.com/downloads/AirPortClient_Update_for_MacBook_and_MacBookPro

I have Macbook Alu unibody 2.4G with this problem.
Airport stopped after the 10.5.8 update.

I downloaded the "fix" and it tells me
"your computer does not meet the hardware requirement for this update"

%!$#!$#!%$$@%!

I don't know whether to cry or laugh. Somebody at Apple please pull your finger out of your *** and get this fixed. Properly.