Here's how you can clean install macOS or OS X on your iMac, MacBook, MacBook Pro without bootable USB drive, external storage medium.
Clean Install macOS / OS X Over the Air, Completely Untethered - All You Need is an Internet Connection
When it comes to installing a fresh copy of macOS or OS X, we immediately divert our minds toward a bootable USB drive from which we will take things off. But really, you don't have to follow the traditional way in order to do a clean installation of Apple's desktop operating system onto your Mac. Everything can be done over the air, completely untethered, and all you need to have at hand is a fast working Internet connection.
But why would you want to take the untethered route? There are a lot of reasons behind it, but I'll focus on only three.
- A USB drive isn't available at all times for everyone.
- Internet speeds are fast enough to get things done at a quick pace.
- You don't have a dongle to connect your USB drive with your (new) Mac.
Before you go ahead with the installation it's worth mentioning here that you will lose your files, therefore make a backup of everything on an external USB drive or iCloud before proceeding. All set? Let's jump into the installation process.
1. Restart your Mac, or power it on, while holding down the Command + R key combination.
2. Release the Command + R key combination once you see the Apple logo on display. In a few short seconds, you'll boot straight into Recovery.
3. Once you see a window like the one below, click on Disk Utility and Erase your main Mac HDD (or SSD). Make sure it's the drive on which you want to install macOS or OS X on.
4. Once the disk is done erasing, close the Disk Utility window. You'll be taken back to the main Utilities page.
5. At this point connect your Mac to a WiFi network by clicking on the WiFi button in the menu bar. Select the network you wish to connect to and enter its password. If you have a the option to connect to the Internet using an Ethernet cable, then you can take that route as well.
6. In Utilities, click on Reinstall macOS or Reinstall OS X.
7. Follow the on-screen prompts for installation and make sure you choose the drive you erased in step 3. This is the target drive where macOS / OS X will boot off from.
8. The process will now begin, but Recovery will first download macOS or OS X from Apple's servers before the actually installation takes place. This may take a while depending on the speed of your Internet connection. It can take as little as twenty minutes all the way up to a few hours.
Once you are done, simply set up macOS or OS X as you normally would.
Alternatively, you can follow the guides below as well in order to install macOS on your computer.