Securely erasing a MacAir

I have an old MacAir that I will be donating to a school. I erased the internal drive but forgot if I was using File Vault or not on it previously. I went to erase the drive again but there is no “Secure Erase” option. If I log on to the Macair and turn File Vault on then after the drive gets encrypted Erase it again, should that mostly scramble/erase any data I had on it before? I know it won’t be perfect but trying my best without having to pull out the drive. Thanks.

If you had built the PC yourself, you would often be able to go to the SSD manufacturer for a utility to do a secure erase. SSD’s are kinda special to erase… they’re not technically byte or bit addressable, they’re broken into pages, and you have to erase a block of pages at a time even to change one bit. (Well technically, they use higher power level, which resets all the affected pages to 1. You can flip individual bits from 1 to zero in theory, but to go back to a 1 you need that higher power again.) So the special utility can have the drive internally go through groups of pages and send the high power to erase them. This has the benefit of getting even the pages that are held in reserve for wear leveling.

Your reference to file vault and secure erase makes me believe that apple does it by encrypting everything to the drive, and if you destroy the keys, it is theoretically securely erased because it would take centuries to find the proper keys. If this was being done all along, then even the reserved pages are probably not a risk. It’s possible that Apple only encrypts “interesting” files… and, for example, the OS files are not considered interesting whereas the user’s files are.

TL;DR If you’ve were using FileVault and you’ve made an effort to format it, you’ve probably done enough. Don’t forget to remove the device from “Find My” before you give it away, or else the new owner won’t be able to use it properly.

Do I still need to do this if I erased the hard drive and reinstalled the OS? Not sure how I can turn it off once I’ve done this.

Yes you still need to do it. You should do it from inside your Apple iCloud account.

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When I try to remove it from another Mac, I see the message below. This doesn’t seem to fully remove it AND again I have already erased the hard drive and reinstalled the OS. Do I have to then create an account, sign into iCloud, and then remove it? I hate to do all of that again since I have it ready to give to the school.

Screen Shot 2020-08-22 at 4.43.57 PM

Well @tokyotony I am not a Mac expert, but I happen to know someone who used to work for Apple phone support a few years ago. He looked at your message and couldn’t really understand what your situation is. He asked me to make sure you don’t have “Lost Mode” turned on. Assuming you have not indicated it as lost, and you select remove to the prompt pictured above, he thinks that’s all you need to do.

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If you are really concerned about completely wiping the hard drive, your Mac has the necessary tool built into Disk Utility. You need to boot into recovery mode, hold down Command and R key and power on (you have to use recovery mode because you are going to erase the drive with the OS on it).
Select Disk Utility when recovery menu appears. Then select the hard drive, and Security Options. Moving the slider will describe the different levels of erasing. Then, find something else to do for a while.

Sounds like you may have wiped the drive and reinstalled the OS. If not, sign out of iCloud first, and that will force you to turn off Find My Mac. If you didn’t do this before wiping it, I suggest you log into your Apple ID and iCloud account, and root around until you find where you can remove devices from your account.

Good luck.

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I don’t know how it is with the Mac, but iPhones can be a real pain, if the previous owner forgets to remove them from their account, before passing them on.

I’ve worked at a company, where an ex-employee had to give his phone back and didn’t remove the phone from his Apple account, it was basically bricked, for us. Apple support told us, we’d have to get the ex-employee to delete it from his account (which he refused to do), there was nothing Apple could do, even though we could prove we owned the device. (It wasn’t worth the legal hassle to sue him for the password to release a 3 year old phone, and he knew it.)

Likewise, a friend of mine runs a phone repair business and often buys old iPhones on eBay and refurbishes them and he has to reclaim about 20% of the purchases, because the phones are already bound to another Apple account.

I’m guessing a Mac will be similar, if it is already linked to one Apple account, you won’t be able to add it your account. (I’m not sure, as I haven’t owned a usable Mac since 2014.)

My friend I mentioned before, who worked for Apple support, was trained to have people disable “Find My” before sending it in for repair or replacement. Even Apple authorized repair agents can’t get around the registration lock.

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My experience with three older MacBook Air’s which cannot go beyond High Sierra is that there is no protection keeping one from wiping the drive, installing the OS from scratch, and using the device as factory fresh.

If you are really concerned, perform the deep nuke, install the OS, and go through the initial setup with a different Apple ID. I believe you will not run into any roadblocks. You can then reset the Mac.

I also believe Apple instituted the protection on iPhone and iPads because they are very susceptible to theft. This protection basically makes them bricks to low tech thieves.

Thanks. Btw, there is no “Security Option” button when I use Disk Utility to erase the drive.

It sounds like many users here have a creative solution for this one and not the actual reasoning behind it.

Apple’s stance in its support notes is that a standard erase is sufficient to securely erase an SSD drive inside an Apple computer and that the secure erase feature had been removed in OS X. This was around 5 years ago.

In the El Capitan security release notes, they make it a point to mention that the “Secure Empty Trash” feature was removed as a solution to the problem because Apple could not guarantee its functionality.

I found this issue and discussion detailed on the StackExchange website. https://apple.stackexchange.com/questions/146733/why-is-a-secure-erase-not-necessary-for-ssds#:~:text=Based%20on%20an%20article%20in,recover%20data%20from%20an%20SSD.

Apple has a support article on “What to do before you sell, give away, or trade in your Mac” (HT201065) https://support.apple.com/en-us/HT201065

So, above all else, Apple would suggest you simply reset the NVRAM, unpair all bluetooth devices and erase/reinstall the drive with OS X.

NVMe based SSDs also have a sanitization wipe procedure, although, I do not believe that Apple has any information on this either.

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Agreed Baconator. i was just going to suggest the process that APPLE lays out on their support page. That is what I have done on two MAC’s that I gave away and traded in.

Drat, Disk Utility bites again. Different every version of MacOS, and can be different in Recovery mode and Internet Recovery mode. Just went through them all.
Secure wipe seems to only be available on external drives. And, to get to it, you have to select the top level of drive, usually identified with manufacturers name, and available if you select All Devices under View on Disk Utility.

One thing I didn’t try was starting MacAir in Target Disk Mode, and trying to wipe it as an external drive from another Mac.

Another alternative is DBAN (Darik’s Boot and Nuke).

Okay, so here is what I did. I went ahead and fully installed High Sierra and then created a user account and logged into iCloud.

I then checked “Find My” on my iPhone and could see the Mac Air using the new account I just created on it. It did NOT reactivate the old Mac Air device in Find My on my phone. In fact, it was still saying “Not connected.” So, lesson learned…at least for an old Mac Air, if you erase the internal drive and reinstall the OS, that computer seems to no long be showing or connected to Find My.

Anyway, I went ahead and followed the steps that Apple suggests when selling your Mac. I am pretty confident that it is no longer linked to my iCloud account (so I can give it away and someone else can use without issue) AND I think being that I encrypted the drive using FileVault TWICE, there should be no usable data on it. If so, oh well. I don’t have access to nuclear codes and all my passwords were in Lass Pass.

Thanks!

I know this post is old but for others that may be looking for this information. There are a couple of options for professionally wiping an apple device.

  1. BC Wipe, is a software that you load up and it securely wipes the hard drive
  2. Parted Magic, is a Linux software that can be used to securely wipe or over write a hard drive.
  3. Blancco, is a paid software that you can buy individual licenses for and wipe Mac, PC, iPhone, iPad, Android devices.
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