RELATED: How, When, and Why to Repair Disk Permissions on Your Mac One of them: volumes on the same drive pool storage space, meaning you’ll see two separate drives in Finder, but won’t have to manage how much storage space each volume uses. To add a new APFS volume, simply select your system drive, and then click Edit > Add APFS in the menu bar. APFS is Apple’s new file system, the default on solid state drives as of macOS High Sierra, and it’s got all sorts of clever tricks up its sleeve. If you want to repartition your system drive, you’ll need to do this from within Recovery Mode, with one exception: APFS volumes. RELATED: APFS Explained: What You Need to Know About Apple's New File System Note: Many of these operations are destructive, so be sure you have backups first. You can also resize, delete, create, rename, and reformat partitions. You can adjust the partitioning layout scheme here. To manage your partitions, click a parent drive and select the “Partition” heading. Each “parent” drive is a separate physical drive, while each little drive icon below it is a partition on that drive. This annoyingly leaves out empty hard drives, but click Views > Show All Devices in the menu bar and you’ll see a tree of drives and their internal partitions.
RELATED: How to Show Empty, Unformatted Drives in Disk Utility on macOS On the left side of the window you’ll see all mounted volumes. Partition Drives and Format Partitionsĭisk Utility shows internal drives and connected external drives (like USB drives), as well as special image files (DMG files) that you can mount and access as drives. This allows you to use Disk Utility to wipe your entire drive-or repartition it. If you booted from a USB disk, click “Continue” to advance to the installer.In Recovery Mode, macOS runs a special sort of recovery environment. If you booted from a functioning recovery partition, click the “Reinstall macOS” button. With your information wipe complete, you are now ready to reinstall macOS.
If you choose three or five passes, you might want to leave this running overnight. If you opted to wipe your drive securely, this might take a while-30 minutes to an hour is not unreasonable for one pass. Just give your drive a name (I recommend “Macintosh HD”, just for consistency’s sake), then click “Erase” to start the overwriting process. You only need to write over a drive once to securely wipe it, but if you’re paranoid you can also wipe it three or five times.Ĭlick “OK” once you’ve decided, but remember: if your Mac has a solid state drive, you do not need to use these options. Now move the dial up, to randomly write data over your entire drive. You still need to wipe the drive, however, or your files will remain in place, so skip to the end of this step to do so.) (If your Mac has a solid state drive, you can skip this part: your SSD will already securely erase files thanks to TRIM. If you’re wiping a mechanical drive, click “Security Options” in the window that pops up. Click your primary drive, then click “Erase” If not you can find Disk Utility in the menu bar: click Utilities then Disk Utility.
To get started, click the Disk Utility option.ĭepending on how you started Recovery Mode, you may be presented with the option to start Disk Utility right away, as seen above. We’ve shown you how to securely wipe a hard drive with your Mac, and doing so in Recovery Mode isn’t really different from doing so within macOS. If you want a truly clean installation, however, you need to first wipe your hard drive. We recommend backing up files before you do this, just in case, but otherwise you’re ready for step three. Your user accounts and files will stay exactly where they are-only your operating system will be overwritten. If you want to re-install your operating system, but leave your files in place, you can skip this step. RELATED: 8 Mac System Features You Can Access in Recovery Mode Step Two: Securely Wipe Your Hard Drive (Optional) Once you’ve managed to open up the Recovery Mode in some fashion, we can move on to wiping your drive securely.
You can access recovery without a partition using Network Recovery: hold Command+Shift+R while turning on your Mac and it will download the Recovery features for you. Failing that, you can create a bootable USB installer for macOS Sierra, and boot from that by holding “Option” while turning on your Mac. If neither of these options work, don’t panic! You’ve got a couple of options yet.