5 Replies Latest reply: Apr 25, 2013 6:36 AM by Bimmer 7 Series
grandmerequilter Level 1 Level 1

Please tell me how I can reinstall Lion on my mid-2012 Macbook Air.  Following an install of ML 10.8.3, my battery life reduced from 7+ hours to barely 2. 


I am not a technie person so please, tell me WHAT to do and HOW (step by step) to do it. 


I am so sorry I installed the upgrade.  Machine had been performing very well. 


Thank you in advance for your help.

MacBook Air, OS X Mountain Lion (10.8.3), Battery life reduced by 2/3
  • grandmerequilter Level 1 Level 1

    Note:  I have read the many, many, (more than 800!) comments regarding this ongoing issue, and since Apple hasn't come up with a fix, I would prefer to return to Lion which worked fine.  I have been using Lion on this machine for 10 months successfully.


    Any and all help would be appreciated. 


    Thank you.

  • Bimmer 7 Series Level 6 Level 6

    Give your Macbook Air a week before you decide to go back to Lion.  Have you checked your brightness settings?  did you turn off bluetooth?


    if you're dead set on going back to Lion, here are your steps.


    turn your computer on while holding down the comman + options + r keys and release once you see the spinning globe - that will do an internet recovery install of the default OS that came with your Macbook Air which is Lion.


    Let me warn you, it will take between an hour to 2 hours depending on how fast your internet connection is.


    Some people have told me that it took 4 hours.  So if you're dead set on going back to Lion - be prepared and be patient.  Best thing to do is to do it before you go to bed.


    Good luck.

  • grandmerequilter Level 1 Level 1



    I ran Time Machine just before I downloaded and installed ML.  Could I just do a restore from Time Machine?


    I'm going to try the things the next responding poster suggested before I do this.  I wanted to have everything synced and iCloud working before my one-to-one membership runs out, but at my local Macusers meeting, I watched a 100% charge completely drain in a two hour meeting.


    Thanks, again.

  • Bimmer 7 Series Level 6 Level 6

    Since I don't use Time Machine - that is something I can't really help you on.  I just usually clone my flash storage with an external drive.


    I have 2 Macbook Air running Mountain Lion and I get over 4 + hours in a single charge.


    What have you got running in the background that's causing your battery to drain fast?


    You can also check your login items to see if there are any applications that starts up automatically when you turn your Macbook Air on. You can get rid of those.


    Also check your activity monitor - see image below - and under all processes - see what's using anything over 10% in your %CPU section - you have to click twice on the %CPU section - once you see apps running over 10% - hightlight and hit quit process.  See if that solves your battery issues.


    Activity Monitor.png