How to securely erase an SDD drive without damaging it?
July 1, 2014 8:48 AM   Subscribe

I have a MacBook Air that I am considering selling. It has an SSD, and I would like to securely wipe it clean before putting it up for sale. I know how to wipe regular hard drives, but I've heard that secure erases of SSD's actually DAMAGE the drive. Is there a secure way to remove data from an SSD hard drive without compromising its lifespan/integrity?
posted by Thanquol180 to Technology (6 answers total) 4 users marked this as a favorite
SSDs are different than spinning magnetic disks because each memory location can only be written to a certain number of times. To account for this, SSDs now use "wear leveling" that distribute writes across the disk.

This has two consequences for you:
  1. You'll need an SSD-specific tool to securely erase the drive. Here's one example for Kingston drives and here's one for SSDs in general. If you don't use these tools, it's conceivable (although really not that likely in my opinion) that someone could recover your data because it'd be stored in an area of the drive that wasn't overwritten by disk eraser designed for spinning magnetic disks.
  2. Erasing the drive isn't really all that bad for the drive because the erases you do will be distributed around the disk. Just make sure not to erase the disk with, say, hundreds of erase iterations, and stick to, say, 10-20. Although some people are exceedingly paranoid about how many times the drive is erased during a wipe, I think that level of paranoia is only justified when you are, say, a representative for a major governmental official. In that case, you should just destroy the disk.

posted by saeculorum at 8:57 AM on July 1, 2014 [1 favorite]

There is no leftover magnetic 'memory' after erasing the drive, hence you don't need to do multiple passes to securely erase your SSD. Follow the instructions from saeculorum and you'll be fine. (Please note that multiple passes were only ever for the paranoid anyway, and the smart paranoid just destroyed the platters - it's quicker!)
posted by defcom1 at 9:57 AM on July 1, 2014 [1 favorite]

With OS X Lion and an SSD drive, Secure Erase and Erasing Free Space are not available in Disk Utility. These options are not needed for an SSD drive because a standard erase makes it difficult to recover data from an SSD. For more security, consider turning on FileVault 2 encryption when you start using the SSD drive.
posted by Lanark at 11:23 AM on July 1, 2014 [1 favorite]

Honestly, just deleting the files and formatting the drive constitutes a secure erase on an SSD to everyone but the NSA. SSDs are not something you can use consumer tools like recuva or the popular SD recovery tools to grab data back from. In addition, all drives apple supplies use some form of encryption to the actual media.

Boot into network recovery with the option key, re-partition and initialize with disk utility, and reinstall the OS. I consider this secure enough for my own SSD equipped mac, and for any clients who inquired about this with me.
posted by emptythought at 3:34 PM on July 1, 2014

In addition, all drives apple supplies use some form of encryption to the actual media.

I am quite sure this is not correct, and that the user must turn on FileVault for there to be any disk encryption on an Apple computer.
posted by Juffo-Wup at 1:14 PM on July 2, 2014

To be clear, i'm talking about the actual physical drive using AES before it writes to the flash chips. You can't read it with software, you can't use some kind of jig to pop the chips out and read them. Get what i'm saying?
posted by emptythought at 3:40 PM on July 2, 2014

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