The very best description of the difficulty conventional tools have in completely erasing an SSD comes from the Electronic Frontier Foundation (EFF.) The article is: “ How to: Delete Your Data Securely on Mac OS X.” Skip to the very last major section labeled: “Secure Deletion on Solid-state Disks (SSDs), USB Flash Drives, and SD Cards.” It’s a long paragraph, but the language is simple as it describes how SSD “ wear leveling” undermines the best efforts of erasure tools to completely overwrite SSD data.Īs a result of how SSDs write data, the best practice today involves going one step beyond the simple process of using Apple’s Disk Utility “standard erase” for an SSD. That last throw-away comment, “for more security,” suggests that there’s a little more to cover, so that’s the next topic.

For more security, consider turning on FileVault encryption when you start using your SSD drive. These options are not needed for an SSD drive because a standard erase makes it difficult to recover data from an SSD. With an SSD drive, Secure Erase and Erasing Free Space are not available in Disk Utility. You’ll also want to read “ OS X: About Disk Utility‘s erase free space feature.” A note at the end starts to get to the heart of the matter. However, that Apple article skips over the nuance of completely erasing an SSD. “ What to do before you sell or give away your Mac.” Item #6 in that document launches the discussion and links to a pretty good article: “ How to reinstall macOS.” That article, by the way, has a nifty table that summarizes which versions of macOS you can install from the recovery partition. The first thing to do is read Apple support article. You’ll want to securely erase that SSD, but it’s a bit tricker than a plain hard disk. These days, because SSDs have been an option for Macs for almost a decade, it’s very likely that you have, or will soon have, a Mac for sale that boots from an SSD. Securely erasing a hard disk isn’t hard to do, and it’s been discussed in many places. Back when I did that last, the Mac had a hard disk.

It’s been awhile since I sold an old Mac. If you’re planning to sell a Mac that boots from an SSD, or you have an old Flash drive or SSD you want securely erase, this article has the details.

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