I have a 2011 MacBook Pro. About six months ago it developed a sleep problem - it wakes immediately on sleeping. Occasionally when recently rebooted it will sleep as it ought, but usually not. On each waking, the log says this:

localhost kernel[0]: (AppleACPIPlatform) Wake reason: ?

Not helpful!

I've done all the obvious things (network, bluetooth, USB) and tried to reset PRAM and SMC, though the latter doesn't seem actually to reset.

More info which might be relevant - occasionally when the Mac is powered off and I plug in the charger, it boots.

Last week the original HD failed and I had a SSD installed. I also upgraded the OS from Snow Leopard to Sierra. The fault has persisted through both these changes. This leads me to wonder if this is a hardware issue.

Only other info about the machine is that it suffered the degrading-solder problem common to 2011 MacBooks. Since it happened before the Apple Repair scheme kicked in, I had it resoldered by a third-party.

Thanks for any help!

Edit: Further to this: a few things I've found: a process called 'hidd' is listed as Preventing Sleep in the Activity Monitor. Its parent is called 'launchd (1)'. And

pmset -g assertions

gives the following:

Idle sleep preventers: IODisplayWrangler

And finally - when I put the computer to sleep, it very briefly sleeps (1s or so), but then HD starts up again. The sleep light goes off, and does not wink or re-light, but the display stays off. To 'wake' it again takes 10-15 seconds.

  • A couple things....Did you have a look at this support article re: waking unexpectedly? Also, when you say you "changed" the OS, did you upgrade (meaning install one on top of the other) or did you do a clean install (meaning you started with a clean slate). If the first, can you try doing a clean install? The reason being is if the problem existed in software, backing up and restoring it to the same computer will just bring the problem over to your new drive.
    – Allan
    Mar 17, 2017 at 12:25
  • Thanks for this! The OS was installed by the computer shop on the new disc - I take it that counts as a clean install? I did then restore a Time Machine backup with my data, after the new OS had been installed. Mar 17, 2017 at 12:31
  • Not necessarily, but they probably (I would hope) did. However, to go from Snow L. to Sierra, you have to go to El Cap first then upgrade to Sierra. Then a restore of Apps and data from TM can "reintroduce" issues. I would start from a clean OS installation. If the problem goes away, you know it's a software issue. Then start restoring things gradually, testing as you go until it fails. Then you will know what's causing it.
    – Allan
    Mar 17, 2017 at 12:44
  • But if Sierra was installed on a clean (brand new) SSD, would it have ever had to go via El Cap? Mar 17, 2017 at 13:48
  • No. Sierra will go on clean and I am assuming that's what they did. If they didn't ( I have seen techs do some really weird things), then they would have had to use El Cap. It's best to verify and be sure.
    – Allan
    Mar 17, 2017 at 13:52

1 Answer 1


Since you're not actually sure if the SMC reset did anything, I'd reset both the NVRAM and SMC again (and in that order) using the steps below.

Before doing so, ensure you have no external hardware connected and that you're using the built-in keyboard.

Reset the NVRAM

Older Macs had what's called Parameter RAM (PRAM), newer Macs use Non-Volatile Random-Access Memory (NVRAM). Here’s how to reset the NVRAM on your particular MBP:

  1. Shut down your machine. Yes, a full shut down, not just logging out.
  2. Press the power button and then press the commandoptionpr keys. You have to make sure you press these keys before the gray screen appears or it won’t work.
  3. Hold those keys down until your Mac reboots again and you here the startup chime.
  4. Let go of the keys and let your Mac reboot normally.

Note: When you log back in you may need to readjust some of your system preferences (e.g. speaker volume, screen resolution, startup disk selection, time zone information, etc).

Reset the SMC

To reset the SMC on your particular MBP, follow these steps:

  1. Shut down your computer
  2. Keep the power cable plugged in.
  3. Press at the same time shiftoptioncontrol (on the left side of the built-in keyboard) and the power button
  4. Let go
  5. Turn your computer back on with the power button.

After resetting both the NVRAM and SMC, use your computer to determine if the issue still persists. IF it does, then test the hardware as per the instructions below.

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.

  • Many thanks for this. I reset the PRAM (definitely successful). Tried to reset the SMC, but as always when I try this, the Mac powers up when I press the key combo, which shouldn't happen. Odd, this. The extended hardware test passed without comments. Mar 17, 2017 at 13:47

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