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My 2011 MacBook Pro is running High Sierra and has a WiFi problem. It stops working after a few minutes and shows "No wifi hardware installed" after reboot. A PRAM / NVRAM reset sorts this out until the next time. SMC reset also temporarily solves the problem.

The computer also has Windows and Ubuntu installed and the wifi works fine in both. Does anyone know a fix for this?

Normally I would just update to fix most Apple problems but the latest update (2018-001) won't install as it will render the Bootcamp partition unbootable!

  • I would bet resetting NVRAM has no effect, but SMC does as SMC is manages power delivery to everything. Next time, try just the SMC reset and see if it fixes. The issue sounds like macOS isn't "restoring" power to the WiFi chipset after being put into a low power mode. Unfortunately this is something only an OS update will be able to fix. The fact that it works properly in Windows/Linux confirms it's not a HW issue. – Allan Jun 4 '18 at 15:02
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I would start with something simple and boot into Safe Mode and test how well your Wi-Fi works while in Safe Mode.

Follow these steps::

  1. Fully shut down your MBP
  2. Restart your MBP
  3. Immediately press the Shift key and keep it down
  4. Let go of the Shift key when you see the login window (NOTE: If you have FileVault enabled you may need to log in twice. Also note that booting into Safe Mode can take a while!)
  5. Take a note of what happens (i.e. can you now connect to the Wi-Fi network and stay connected?)
  6. Exit Safe Mode by restart your MBP as normal and test again

The act of booting into Safe Mode will actually perform a number of background tasks, and this often resolves issues when you've rebooted normally.

Once you've tried the above let me know how you go.

[Update 1]

Since we've established the issue is still present during Safe Mode and that it still keep recurring after resetting NVRAM, let's next test your hardware for signs of any problems.

Run Apple Hardware Test

Your model MBP uses Apple Hardware Test. To use this, follow these steps:

  1. Shut down your MacBook Pro
  2. Restart your MacBook Pro
  3. Press and hold the D key before the gray startup screen appears.
  4. After a while, Apple Hardware Test (AHT) will start.
  5. When prompted, select your language and click the right arrow.
  6. When the AHT console appears, you can choose to run Basic tests by clicking the Test button. However, I suggest you select the "Perform extended testing" checkbox before you click the Test button.
  7. Your test results will appear in the window in the bottom-right of the console.

Note 1: that the extended test will take some time. Take a note of the results and report back.

Note 2: If pressing and holding the D key at Step 3 doesn't work, start again at Step 1 and, at Step 3 press and hold both the OptionD keys instead. This will try and run diagnostics from the internet instead, so you will need to allow more time for it to complete.

[Update 2]

Another option worth trying is to remove your Wi-Fi service, restart, and add your Wi-Fi service back.

To do this:

  • Go to Apple > System Preferences > Network
  • Select the Wi-Fi service on the left-hand side
  • Click on the cog icon at bottom-left and select Make Service Inactive
  • Now delete the service by clicking on the minus sign (i.e. the - button) at left of the cog
  • Click on the Apply button
  • Exit Network preferences
  • Restart your MBP
  • Go to Apple > System Preferences > Network
  • Click on the plus sign (i.e. the + button) at left of the cog
  • In the pop-up window, ensure that Wi-Fi is selected from the drop-down menu
  • Click on the Create button
  • Make sure Wi-Fi is on and connected (it should remember your previous settings, but if not just re-add your Wi-Fi network again)

Let me know how you go.

  • I can confirm that the Wi-Fi did not work while in safe mode. I have performed yet another PRAM/NVRAM reset and it is now working for the moment. – Simon Baldwin Jun 2 '18 at 16:34
  • No worries, good to know. If the issue returns then we may need to do some hardware diagnostics and, assuming that's okay, some wireless diagnostics too. All the best! – Monomeeth Jun 2 '18 at 23:25
  • The issue returned the next time the computer slept. On normal restart "Wifi Hardware not installed" Wi-Fi returned after a PRAM/NVRAM reset as usual. I am performing a reset every time I boot into Mac OS. – Simon Baldwin Jun 3 '18 at 23:07
  • Ok, I've updated my answer on how to run Apple Hardware Test. Let's do that next and we'll go from there. – Monomeeth Jun 4 '18 at 2:40
  • Hardware test shows " No problems" and Wi-Fi is working again for the moment, even after a short sleep. – Simon Baldwin Jun 4 '18 at 20:14
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This actually turned out to be a hardware problem. Luckily I only had to check the ribbon cable connections to the Wi-Fi card and push it on firmly to restore Wi-Fi in all three operating systems. The advice above was very helpful in ruling out software as an issue.

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Had similar situation going on with my 2011 MacBook pro. Had tried resetting PRAM & SMC, and nothing really happened. I found that I could re-start the machine and sometimes wifi worked, other times, it did not. After reading the above information, it make perfect sense - a laptop will endure countless micro-shocks, every time it is set onto a table, there is a slight vibration.

So, I opened up the computer and found that the plugs are oriented to face upward and plug-in from beneath the wifi antenna. Thus, every downward shock will work against this orientation until the connections eventually become tenuous such that they only work from time to time.

The fix is super simple: just remove the bottom of your MacBook and unplug and replug each wire going into the wifi device.

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