Macbook Pro 9,2 (2012) - Downgrade from High Sierra to what?

Discussion in 'macOS' started by lorthax, May 25, 2018.

  1. lorthax, May 25, 2018
    Last edited: May 25, 2018

    lorthax macrumors newbie

    May 25, 2018
    Hello everyone,

    The RAM is 4GB. I made a mistake of updating my Yosemite OS to High Sierra. It is now very lagging and the battery ran out very fast. I'm very illiterate in all these things about computers and all, I'm going to need a step by step guide for the downgrading process.

    However before we're getting to anything, which would be the best OS for me to downgrade it to?


    I read this thread that people recommended the person to upgrade his/her SSD. But will it still drain my mac battery if I continued to operate in High Sierra?

    Thank you so much for your help
  2. Fishrrman macrumors P6


    Feb 20, 2009
    I'd suggest 10.12 "Low Sierra".

    But you have "a long road" ahead of you, and it's going to require that you learn to become "more computer literate", or you're not gonna get there.
  3. lorthax thread starter macrumors newbie

    May 25, 2018
    Okay.. As I understand it, I'm gonna have to create a bootable USB drive for the OS.

    The problem is, I only have the Maverick, Yosemite, and High Sierra installer purchased in my app store.

    Am I that screwed?
  4. Fishrrman macrumors P6


    Feb 20, 2009
    Some links to check for obtaining Low Sierra:
    (might need to try more than one, the object is to download the Low Sierra installer app)

    Again, it will be up to you to try each and see if one works for you.


    - Download CarbonCopyCloner from here:
    CCC is FREE to download and use for 30 days.

    - You will need AN EXTERNAL DRIVE that is formatted to Mac OS extended with journaling enabled (NOT APFS)

    - Use CCC to create a cloned backup of your drive AS IT IS NOW onto the external drive. MAKE SURE that you have CCC set to create an HFS+ clone. YOU DO NOT WANT TO CREATE AN APFS CLONE (or you may not be able to access it later on).

    You can skip the above if you don't care about anything that is on the internal drive now. But... I recommend that you do this anyway. Otherwise you'll lose any data on the drive.

    Once you have created the cloned backup, and you have the installer app, do this:
    - You will need a USB flashdrive 8gb or 16gb, formatted to Mac OS extended with journaling enabled.
    - You will need the free app named Boot Buddy, get it here:
    - Use Boot Buddy to create the bootable USB installer (it may take a while)

    You can boot the Mac from the USB flashdrive by pressing the power on button and IMMEDIATELY holding down the option key CONTINUOUSLY until the startup manager appears.
    Do you see the flashdrive installer?
    If so, click it to select it and hit return.

    It will boot to the OS installer, but DON'T RUN IT YET.
    Quit the installer and open Disk Utility.
    "Aim" DU at the internal drive and ERASE IT to Mac OS extended with journaling enabled.
    The "topmost icon" for the internal drive is the PHYSICAL DRIVE, this is the one you must choose.

    If this works, re-open the OS installer and install the OS. It may take a while with one or more reboots.

    When done, you should see the setup screen for Low Sierra.
    You can create an account for yourself.
    If you can get this far, you can "manually migrate" your data from the cloned backup.
    But you need to get this far first.
  5. mikzn macrumors 6502a


    Sep 2, 2013
    If you don't have an SSD it will be a huge speed increase and very easy to upgrade a 2012 MBP

    here is a link on the replacement procedure

    I did this on several 2012 MBP very easy - I used the samsung evo 850 ssd - it will be 10 times faster - especially when starting. Probably not much better for battery life tho.
  6. lorthax thread starter macrumors newbie

    May 25, 2018
    What is this HFS+ clone?

    Is that any different from the regular copy > paste all of my mac's data to a HDE?

    Wow really, thank you so so much for your guide. Is that really all? Thank you, really!!

    I think I'm just going to upgrade the SSD and change the battery so that I can use this mac for another 3 years. Thank you!

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