If you’re planning to sell your Mac or just want to completely erase and restore your hard drive, then this step-by-step guide is for you. Following this guide, you’ll be able to wipe your Mac hard drive clean and reinstall the operating system in no time.
Before you start the process, it’s crucial to back up your computer completely. Whether it’s on Time Machine or through drag and drop, make sure to save all of your important files to an external hard drive. Once you start this process, all the information will be deleted forever.
Once you’ve backed up your files, log out of the Message app, sign out of iTunes, de-authorize your computer from using iTunes, and sign out of your iCloud. Afterward, shut down your computer.
Next, hold down “Command R” and turn the power on if you plan on keeping the computer. If you’re selling the computer and giving it to someone else, hold down “Option Command R.” The startup will take a little bit longer while doing this, but you need to continue to hold the command and the r button down until you see the Apple logo and then you see the progress bar starting below.
Afterward, you’ll see the Mac OS Utilities, where you’ll need to select Disk Utility to completely erase all information off the hard drive and then reformat it.
Under the internal section, you’ll see your hard drive. If you’re running Catalina, you’ll have one just below it that looks like the exact same thing and is labeled whatever you’ve named your hard drive. In that circumstance, under this, you’ll have Mac SSD/data. For everyone else who’s not running Catalina, you’ll only have one hard drive here.
If you’re running Catalina, select the top one and click the minus button to get rid of groups. If you’re not running Catalina, select your hard drive and click erase. Name it whatever you want to name it and format it accordingly. If you have an SSD drive, format it the APFS way. If you don’t have one, it’ll say Apple extended journal. Once you have the one identified, click erase, and it’ll automatically wipe your hard drive clean and then reformat it.
Once you’ve done that, go back to the main install screen and click on Install Mac OS. On the welcome screen, click continue, agree to the basic terms of the software, and click on the hard drive you just reformatted. Click install to start installing. Depending on your internet speed, this could take anywhere from 15 to 45 minutes.
Once it’s done, you’ve successfully wiped your computer clean, reformatted the hard drive, and reinstalled the operating system. If you’re selling the computer, you can power it down from this point, and the new user can enter all their information and set it up exactly the way they want it.