The 'ATA Secure Erase' command instructs the drive to flush all stored electrons, a process that forces the drive to 'forget' all stored data. In basic terms, this means when you delete a file in your operating system, the TRIM command wipes the space and makes it available for use. The TRIM command marks the blocks of data the SSD is no longer using, ready for wiping internally. Solid-state drives use a specific command to keep on top of file deletion, known as TRIM. At least, not how they work on a magnetic hard drive. What that does mean, however, is that some common secure file deletion methods don't work as you would expect. Your SSD constantly moves data around to comply with wear leveling, ensuring all blocks wear at an even rate. Basically, your computer has no way of telling 'where' that information was just copied to. In other words, SSDs do not use any physically indexable locations, and software cannot specifically target sectors on the disk. Changes made for wear leveling record to a separate file map. Your Mac will begin wiping the drive.While the SSD uses a file system to communicate data storage locations to the host system, it also re-shuffles the data to ensure even wear across all memory blocks. When you’ve picked how many wipes you’d like to run, click “OK,” then click “Erase” back at the initial prompt. Seven passes is going to take a long time, and even three passes will take at least an hour, so only use these options if you’re really, really paranoid. The Pentagon is even more paranoid: they use seven passes. But three passes is what the US Department of Energy uses to securely delete their files. RELATED: You Only Need to Wipe a Disk Once to Securely Erase ItĪs we’ve discussed before, you probably only need one pass, at least with modern hard drives. The first notch to the right of “Fastest” writes over the entire drive with random data once the third notch, three times.

That’s not what we want, so let’s move the slider. The first option, “Fastest,” will delete the partition but leave all files untouched. You’ll see a sliding scale with four options: Click the “Security Options” button on the bottom.

Mac disk utility secure erase time