How to erase everything on a Mac desktop?

January 5, 2017 8:47 AM

I have to return my Mac desktop to the job I just left. I've been careless about using it as my home computer too, downloading photos, looking at my bank accounts, etc. Is there a fast and easy way to delete everything on there?

I haven't installed anything except Chrome. (No Word, etc.) All my passwords are auto-saved, I have screenshots of various banking stuff in the downloads file, etc. What is the fastest, easiest way to empty it, deauthorize it for iTunes, and keep the next owner from knowing my personal information?

I don't need to clone or keep anything on there. Is this the best set of steps for me? http://www.macworld.co.uk/how-to/mac/how-reset-macbook-air-pro-imac-restore-your-mac-original-factory-settings-macos-3494564/

posted by pipti to Computers & Internet (14 answers total)

What you've done is more than enough for most home users -- your old data is gone unless the NSA wants something off your computer.

If you're feeling extra cautious, enable File Vault, let it encrypt your drive, and then erase the encrypted drive using the method outlined in your original link.

http://www.macworld.com/article/2906499/mac-911-how-to-erase-your-macs-hard-drive-the-right-way.html
posted by nathan_teske at 8:56 AM on January 5, 2017

www.dban.org this will completely wipe the computer and require the reinstallation of the OS.
posted by tman99 at 8:57 AM on January 5, 2017

Nathan-Teske, I haven't actually done anything yet. When you says "what you've done" do you mean the set of steps I linked to?
posted by pipti at 8:59 AM on January 5, 2017

Yes exactly -- the only difference is that you first let File Vault encrypt the disk. It adds a little bit more security because it's first overwriting the entire volume with encrypted data.
posted by nathan_teske at 9:01 AM on January 5, 2017

One easy route is take it to a mac store, tell your local genius you want to wipe the machine and put a clean install of the latest OSX on it. They have a little USB thing they can plug in and it takes about 15 min and it will be shiney and clean.

This is how I do regular upgrades when new versions of OSX come out. I like clearing out the cruft.
posted by jeffamaphone at 9:20 AM on January 5, 2017

If you do decide to go down the "wipe it all" route, make sure there is no work product or other company specific applications/licences etc. that are not yours to delete or may be an issue if its "not returned". I can imagine that's far less of an issue for some organizations that will simply wipe and reinstall systems between users as standard and have all the data you worked on backed up etc, versus others who may take exception to having to try rebuild a system you've wiped or frankly may be suspicious of a system coming back having been wiped. Obviously totally variable depending on your employer, what your employment role was, the data you had access to, and your situation leaving the company etc.
posted by inflatablekiwi at 9:40 AM on January 5, 2017

To clarify and expand on what nathan_teske has said:

There are two parts to the data stored on your hard disk: the actual data, and the index to the data, which tells the computer where to find the data it wants. Following the steps in the article you linked will remove the index to the data, so the computer won't be able to find any of your data, but it won't delete the data itself. So no one's going to accidentally stumble across your private data, but if someone who was fairly technically savvy and sufficiently determined wanted to try to get at your data, they could probably reconstruct all or most of it. Think of it like locking your door. An ordinary lock will prevent a stranger from casually wandering in to your home, but it won't prevent someone sufficiently determined from breaking your door down with a sledgehammer, or getting a locksmith to open the lock.

If you use File Vault to encrypt the disk before you do a factory reset, that means that the underlying data will be encrypted. Without the password that you used to encrypt the disk, your data will require serious encryption-cracking power to recover. Think of this like hiding your data in a safe. It's still possible for someone to get at it, but the expertise and tools needed are very rare and don't come cheap.

There are also utilities that will actively overwrite the data on your drive, making it almost impossible to recover, but finding and figuring out how to use one of these is probably not worth the effort unless you're worried that powerful people with access to considerable financial and technical resources are going to try to get at this data.
posted by firechicago at 11:23 AM on January 5, 2017

I don't think I need to do anything particularly heavy-duty—just make it like I wasn't there for the next person who uses the computer. Is there an especially easy way to do this?
posted by pipti at 11:31 AM on January 5, 2017

[This assumes that you have copied all the data that belongs to you to another computer/thumb drive/GDrive/etc, and have nothing left on the computer that you personally need.]

1. System Preferences -> Users & Groups

2. Click the lock (bottom left), enter password.

3. Click on "plus" symbol at bottom left, create new Administrator account, username "MyExCompanyName," leave password blank.

4. Apple Menu -> Log Out pipti...

5. Choose "MyExCompanyName" from the Login window (no password required).

6. System Preferences -> Users & Groups

7. Click the lock, no password should be required.

8. Select pipti account from left hand side, click on "minus" symbol on bottom left, select "Delete the home folder," and click "Delete User."

Done! This leaves any company software packages installed, but deletes your home directly entirely -- leaving behind a brand-new user account for your IT staff to start from.

*One note -- check to make sure you didn't leave any files in the root directory of your hard drive; double-click on your Macintosh HD, where you should only see four directories, nothing else (Applications, Library, System, Users). Also, drag Chrome to the trash and empty the trash.
posted by liquado at 12:12 PM on January 5, 2017

The most expedient solution is to simply enable FileVault and let the drive encrypt itself. Then ensure that the Guest account is disabled and all other accounts have good passwords (since any of them can unlock the drive).

There is no step 3. Your disk is effectively erased to anyone who doesn't know the password. (Fun fact: The "wipe this computer remotely" thing in iCloud doesn't actually erase the disk -- it just throws away the master disk key.)

If you already have FileVault enabled and a good password and no Guest account and you're not logging into a remote user account (like a Windows domain), you're already set.

You should probably avoid DBAN, it might erase the OS X recovery volume as well.
posted by neckro23 at 2:34 PM on January 5, 2017

As liquado says, make a new admin account, log out of your real account, log into new admin account, delete your real account. It's that easy.
posted by w0mbat at 2:40 PM on January 5, 2017

How do I know if I have Filevault enabled? (I do use a password to log on when the computer first boots up.)
posted by pipti at 3:50 AM on January 6, 2017

How do I know if I have Filevault enabled?

System Preferences > Security & Privacy > Filevault

It will say if it is turned on or off.
posted by w0mbat at 10:33 AM on January 6, 2017

Thanks everyone for your good advice. I ended up deleting the hard drive and re-installing the OS.
posted by pipti at 8:38 AM on January 30, 2017