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I want to reset my Macbook Air Early 2015 but not just simply deleting the disk and reinstall it with macOS Utilities menu. What I mean is "full factory reset." I want it to be like it just left the factory, at least in the software side. Like SMC and NVRAM reset etc. Or deleting the disk resets the things that I mentioned?

If not, when should I reset them? After deleting the disk and before installing the High Sierra (I will downgrade from Mojave to High Sierra) or after installing the High Sierra?

And are there any other things that can be reset like SMC and NVRAM? If there are, please mention them.

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  • Is there a specific reason you want to do this? Having more details on this will help in finding good answers.
    – nohillside
    Nov 25, 2020 at 23:00
  • PS: You don‘t need to reset anything in order to downgrade to High Sierra.
    – nohillside
    Nov 25, 2020 at 23:01
  • In my previous question, I mentioned that I have a battery problem. As far as I was told, and in all likelihood it is, there is a battery failure. Or to be more exact, my battery has reached end of his life. But maybe there is a software issue and I won't have to spend money on a new battery. That's the reason why I want a "full reset." By the way, why did you delete my remercy part? :) Is it a rule or something?
    – Efe
    Nov 25, 2020 at 23:45
  • The SMC handles calculating the battery % remaining, so a software reinstall won't fix it. The OS just reads the data from the SMC. The remercy is "out of place" as you're not writing a letter/email. You just need a well articulated question. See, this blog under the section "Making a Good Impression".
    – Allan
    Nov 26, 2020 at 0:49
  • OK I will keep in mind when I write another question. I just wanted to be polite but apparently those sentences just take up space here, sorry.
    – Efe
    Nov 26, 2020 at 1:18

2 Answers 2

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There are so many terms used in the question that indicate a misunderstanding of what a "full factory reset" is.

First off, your MacBook Air (or any computer and not limited to Apple) is not a phone; there's no "factory reset." In fact, "full factory reset" is not correct either. You can "reset to factory defaults" which is a term used for wiping the custom configurations of your device so that it will behave like it was just removed from the box. It doesn't, however, return it to the OS/firmware that it originally shipped with. If you applied any firmware updates, you can't roll those back - and it wouldn't be prudent to do so.

I want it to be like it just left the factory, at least in the software side. Like SMC and NVRAM reset etc.

The SMC and NVRAM have absolutely nothing to do with software. The SMC handles power, battery charging, fan control, etc. There's nothing in the SMC that has anything to do with how you personally interact with your computer; there's no identifiable information. The NVRAM sets your pre-boot environment variables and your Find My Mac token. There's nothing in NVRAM that's personally identifiable and necessary of resetting.

I wrote an a short piece on what Resetting the SMC and NVRAM actually does. (it's part of a broader answer). It's not necessary to reset either of these.

Or deleting the disk resets the things that I mentioned?

No. I assume you mean erasing your disk. Your disk contents has nothing to do with the SMC. As far as your NVRAM goes, pretty much the only entries in NVRAM related to your disk is where the the boot and recovery partitions are located and this info rarely changes from computer to computer. You could reset it, but it will likely go back to what it was before.

After deleting the disk and before installing the High Sierra (I will downgrade from Mojave to High Sierra) or after installing the High Sierra?

Why downgrade? Most users would want to know that the Mac runs the latest and greatest operating system, not one from three years ago (2017). However, if you want to go this route, all you have to do is boot using the keyboard combo ⇧ Shift⌘ Command⌥ OptionR. This will install the version of macOS that came with your Mac or the closest version still available (this one reason is why "full factory reset" is not applicable to computers).

See: How to reinstall macOS from macOS Recovery

TL;DR

And are there any other things that can be reset like SMC and NVRAM? If there are, please mention them.

As mentioned, SMC and NVRAM reset are useless - doing this will accomplish nothing. It won't hurt anything if you do so, if you feel better doing it, have at it. I just want to make you aware that these resets, that are way too often cited, aren't very relevant.

What you should do is the following:

  1. Ensure you've backed up your data

  2. Sign out of iTunes/Music (de-authorize your computer), iCloud, Messaging, etc.

  3. Remove any accounts you may have added (like Mail, Exchange, Social networking, etc.)

  4. Unpair any Bluetooth devices you may have connected

  5. Remove any firmware and File Vault encryption passwords you may have enabled

  6. Wipe your drive and reinstall macOS

    • ⌘ CommandR - Install the latest macOS version installed with your Mac
    • ⇧ Shift⌘ Command⌥ OptionR - Install the version that came with or closest to when your Mac was shipped from the factory
    • Before proceeding with the installation of macOS, use Disk Utility from the Recovery Boot Menu to wipe your drive
  7. Turn off your computer once you get to the "Welcome" screen. When the new user gets it and turns it on for the first time, they will get the "new computer experience" like it came from the factory.

The key is to un-link your Mac from you both physically and online. Removing firmware and File Vault passwords will ensure the new user can use the Mac without going back to you for them. Wiping the drive ensures your data is gone and not just "hidden" in a different user account. Removing online links (i.e. iCloud) ensures the new user can link it to their account and keeps you and your data out of the mix.

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  • Thanks a lot for your detailed explanation. If you remember, 2 days ago I asked a question about my battery problem. As far as you said there, this is a battery malfunction. But what if it isn't? What if it's just a software issue? Probably it isn't but there is no harm in trying. And I'm and old school person, I don't know why but updates are kind of irritate me. So it can be said that I will use my battery problem as an excuse. But could you please tell me if there is something that can be reset like SMC? And when should I reset them, before the installation or after the installation?
    – Efe
    Nov 26, 2020 at 0:04
  • Since the SMC handles charging, resetting it in that case makes sense. However, software is not going to prevent your battery from holding a charge - remember, the battery can charge and be discharged with no operating system installed whatsoever, so software issues are highly improbable. There's no other hardware (other than SMC or NVRAM) that can be reset - those are the only two. If you must reset, do it after installing the OS. It will force a reboot and you can confirm everything works when you do them.
    – Allan
    Nov 26, 2020 at 0:12
  • Okay thanks. I doubt whether the algorithm, or whatever performs the processes, in the software somehow leads to a miscalculation of the battery percentage, health or something. I will try as soon as possible. I hope it works!
    – Efe
    Nov 26, 2020 at 0:40
  • The only thing influencing the charge limits is the BMS, which is integrated in to the battery and cannot be reset. A 2015 is likely to have a worn out battery regardless of use. To fix it, it needs replacement. Nov 26, 2020 at 3:58
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Here is the checklist for a full reset of a Mac.

It covers most of the accounts people tend to forget. Yes, you do want to turn of FileVault to encrypt all data. Then do the cryptographic erase, install from recovery to upgrade all firmware with the latest OS.

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