How to do a clean install of macOS Mojave 10.14

Apple promised and delivered: the macOS Mojave 10.14 it's between us! And, as we mentioned in the system release article, there are two ways you can install it: 1. simply by logging into the Mac App Store and downloading the update, or 2. installing the system from scratch, which we call clean installation.

Before installing

Regardless of the option you choose, it is very important to always make a backup.

The testing phase of operating systems is long mainly to avoid serious problems in the upgrade process, but since no perfect software (and you run risks like even running out of power in the middle of the process), it is good to be on your guard.

The simplest way is to use Time Machine itself, a backup system built into macOS. If you already use it, just open System Preferences and check, before installing Mojave, if everything is activated correctly and if the last backup made by it is recent (even today, because it runs hourly).

Time Machine, however, saves absolutely everything on your Mac (including "junk" and traces of previous operating systems that you might be looking to get rid of). My recommendation here, then, is to get an external HDD / SSD, a pendrive, an SD card or even use a cloud service of your trust to manually save all important files that you cannot be without.

If you use iCloud, you don’t have to worry about emails, contacts, calendars, notes, reminders, passwords in Safari, photos (as long as you use the iCloud Photo Library feature) and documents (which are on the Desk and in the Documents folder, as long as you are using the feature that sends all this to iCloud).

What is a clean installation?

A lot of people like to take advantage of these releases of great new operating systems to make a clean installation, that is, erase everything and start over from scratch without any "trash" / traces of previous installations.

The good thing about a clean installation is that by getting rid of this “junk”, you can save a few gigabytes. And, by pulling your files back into the new system, you can take the opportunity to organize everything better and even discard some things that no longer make sense to keep (this, of course, is an individual assessment that only you can do).

The downside of a clean install is that you will have to install several third-party applications on your Mac again and configure them the way you are used to using them.

How to do a clean installation?

There are two ways to do this: using the macOS Recovery feature or by creating a boot disk.

USING THE MACOS RECOVERY FEATURE

As of macOS Sierra 10.12.4, Apple has implemented a very cool feature. With it, just restart the computer with the R keys pressed to begin the macOS installation process. The cool thing about all this is that, using the mentioned shortcut, the installed system will be the latest version of macOS compatible with your Mac so, if your one of the ones listed above, you can install macOS Mojave 10.14 this way.

The downside of installing via Recovery for macOS is that your Mac will become unusable during the download period of the operating system. And since it can take a few good minutes / hours (depending on your connection and Apple's servers), it can be quite annoying.

It is worth noting that, to do the clean install, you need to erase the boot disk before installing macOS. Remembering that by permanently erasing the boot disk, all data stored on it is erased! Then, confirm that everything you need is in fact in your backup.

Once this is done, follow the instructions below:

1. Select "Disk Utility" in the macOS Recovery utilities window and click "Continue".
2. Select the device or volume in the Disk Utility sidebar.
3. Click on the "Delete" button or tab.
4. Fill in these fields: Name: enter a name for the disk, such as “Macintosh HD” .Format: select Expanded Mac OS (Time Record) or APFS. Scheme (if available): select “GUID Partition Map”.

   

5. Click "Erase" to start erasing the disc.
6. When finished, exit Disk Utility to return to the utility window. You are ready to install macOS.

CREATING A START-UP DISK

Do you know the problem of making your Mac unusable while downloading macOS Mojave 10.14? Well, that doesn't exist when choosing to create a bootable disc. To do this, you will need to use an external HDD / SSD, a flash drive or an SD card (if your Mac has a slot for cards or you have an accessory for that) to be your boot disk. Choose a disk that can be formatted (with a name without spaces and without special characters, preferably), as the system itself will clean it.

You can choose one of the two ways to create your installation disc, using the Terminal or an app.

By Terminal

1. Download macOS Mojave from the Mac App Store.
2. When it opens the installation window automatically, close it using the shortcut Q.
3. In the Finder, open the "Applications" folder, right-click on "Installing macOS Mojave" and select "Show Package Contents".
4. Comes Contents Resources and leave this window open.
5. Open another Finder window (New Finder Window File or by shortcut N).
6. Comes Utility Applications and open the Terminal.
7. In the window that opens, type sudo followed by space.
8. Now, in that window that you left open, drag the createinstallmedia file to Terminal.

   

9. Type –volume followed by space.
10. With the Finder selected, go to the menu Go Go to Folder.
11. Type / Volumes and click "Go".
12. Connect the external HDD / SSD, flash drive or SD card to your Mac and it should appear on the table.
13. Drag its volume (cone) to the Terminal window.
14. Press Enter to finish sending the command.
15. If necessary, enter your password.
16. Type y (from "Yes") to allow the external disk to be erased and press Enter.

    

17. The installation process will start, deleting the contents of your external HDD / SSD, flash drive or SD card and copying the installer files to it, remembering that this whole process can take a while (about 20 to 30 minutes).
18. When the process is complete, you can use this external HDD / SSD, USB stick or SD card to boot the macOS Mojave 10.14 installer.

If by chance, during this process, an alert appears asking about “SetFile”, you can choose the option “Now No” ("Not Now") as this will not interrupt the creation of the USB installation drive.

Using an app

If you are not familiar with the Terminal and do not like the way the above process is performed, you can choose to do everything using an app. The free DiskMaker X 8 and a hand on the wheel it has instructions for the process of creating the disc, just follow the step-by-step.

DELETING YOUR MAC AND INSTALLING THE NEW SYSTEM

1. Restart the computer by holding down the key (Option) during the reset.
2. Select the created external disk.
3. Select Disk Utility and click "Continue".
4. Select the device or volume in the Disk Utility sidebar.
5. Click on the "Delete" button or tab.
6. Fill in these fields: Name: enter a name for the disk, such as “Macintosh HD” .Format: select Expanded Mac OS (Time Record) or APFS. Scheme (if available): select “GUID Partition Map”.
7. Click "Erase" to start erasing the disc.
8. When finished, exit Disk Utility to return to the utility window. You are ready to install macOS.

After the installation is complete, add your files back to the Mac, either by retrieving them via Time Machine or dragging them from your external drive via the Finder.

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And, who's already running macOS Mojave 10.14? All right? 😉