Install Linux on an Intel Mac

Keep macOS. That’s the advice for a first install on any Mac, and on a Mac from 2018 to 2020 it’s close to an instruction, because the wifi driver for those machines has to be copied out of a working copy of macOS. Give Linux half the disk, get a menu at startup asking which one you want today, and remove macOS in a year if you find you haven’t opened it.

The exception is a Mac you’ve already retired. If it’s the 2012 MacBook Pro in the drawer, erase the lot and enjoy the space.

Before you start

Three things should be true. Your files are backed up to an external drive and you’ve opened a few from it. You’ve run Mint from the USB stick on this Mac and the screen, sound and trackpad worked. And you know whether your Mac has a T2 chip, from the Mac guide, because the T2 changes two of the steps below.

If FileVault is on, Disk Utility may refuse to make room on the disk. Open System Settings, then Privacy and Security, and turn it off. Decrypting takes a while on a big disk, and it needs to finish before you go any further.

Plug the Mac into the wall. Then start from the stick as before, holding Option at power-on and choosing EFI Boot.

Make room in macOS first, if you’re keeping it

Mint’s installer offers to shrink Windows and slot itself in beside it. It makes no such offer for macOS, since it can’t safely resize Apple’s disk format, so you make the room yourself before you start.

1. In macOS, open Disk Utility, which lives in Applications, then Utilities.
2. Select the internal disk in the left column, the top item, not the volume underneath it.
3. Click Partition in the toolbar. If a box asks whether you want to add a volume or a partition, choose Partition.
4. Press the plus button under the pie chart. Give the new slice a name such as Linux, set its format to MS-DOS (FAT), and drag it to the size you want. Mint wants 20 GB and is happier with 100 GB.
5. Click Apply and wait.

On a T2 Mac the t2linux guide warns that you won’t be able to change this size later, so pick one you can live with. The format doesn’t matter, since Mint’s installer will erase this slice and use its own. Its only job is to be the empty space the installer finds.

The installer, screen by screen

1. Double-click Install Linux Mint on the desktop and choose your language.
2. Connect to the internet if you can. On most Macs the wifi icon shows nothing yet. That’s fine, and the fix comes after the first restart. Tick the box offering multimedia codecs, which is what lets ordinary video and music files play.
3. Choose the installation type. If you made a slice in Disk Utility, choose Something else. Find the partition you made, which is the one whose size matches and whose type says fat32, select it, and click Change. Set Use as to Ext4 journaling file system, tick Format, and set Mount point to a single forward slash. Leave every other partition alone. The one called EFI System Partition is where the Mac keeps its startup files, and Mint shares it without harm.
4. If you’re giving Mint the whole Mac, choose Erase disk and install Linux Mint instead, and the installer handles the rest. Read this screen twice. Both options are on it.
5. Pick your time zone and keyboard layout. Under your language, look for the variant labelled Macintosh, which puts the @ and “ keys where the caps say they are.
6. Enter your details. Lowercase username with no punctuation, which Mint’s guide recommends to prevent bugs, and a password you’ll remember, because Linux asks for it whenever you install software. If the laptop leaves the house, tick Encrypt my home folder.
7. Wait. There’s a slideshow.

When it finishes, restart, and pull the stick out when the screen tells you to.

The first start

The Mac should start straight into a plain text menu with Linux Mint at the top and, further down, an entry for macOS. Do nothing and Mint starts after a short wait.

If it starts into macOS instead, it’s because the Mac’s firmware still prefers Apple. Hold Option at power-on, pick the entry that isn’t Macintosh HD, and Mint starts. To make Mint the default, start macOS, open System Settings, then General, then Startup Disk, and see whether the Linux entry is offered. On many Macs it isn’t, and holding Option becomes a habit that takes two seconds. A small tool called rEFInd fixes this properly if the habit annoys you, and it’s a search away.

Go into macOS once, now, to confirm it’s still healthy.

The wifi fix

Back in Mint, if the network icon still shows nothing, open the menu, then Administration, then Driver Manager. It will ask for your password and then complain it can’t reach the internet. Plug the Mint USB stick back in, and Driver Manager offers to use it as the source. Say yes. It lists the Broadcom wireless driver, already ticked. Click Apply Changes, wait, and restart.

After that restart the network icon lists your wifi like any other laptop. If wifi was the only thing that failed from the stick, this was the whole fix.

Then open Update Manager, the shield near the clock, and let it install what it finds. It’ll be a lot the first time.

If your Mac has a T2 chip

Two of the steps above change.

The stick is the t2linux build of Mint rather than the standard one, as the trial guide explains, and Startup Security Utility has to be set to No Security with external boot allowed before the Mac will look at it.

Wifi and Bluetooth aren’t fixed by Driver Manager. The driver is already built into the t2linux version, and what’s missing is the firmware, a small file Apple’s licence forbids anyone from distributing. The t2linux wifi guide walks through copying it out of your macOS installation with a script. It’s the one step here that involves the terminal, the script is short, and it’s the reason macOS stays on the disk.

Once it’s done, the Mac runs Linux with working wifi, sound, Thunderbolt and the Touch Bar in its plain function-key mode. The webcam won’t, and there’s no fix for that yet.

What you’ll notice in the first week

Two-finger scroll goes the opposite way from macOS. Open Mouse and Touchpad in the settings and turn on natural scrolling, which puts it back.

The Command key is now Super, which on a PC keyboard is the Windows key. Copy and paste are on Control instead. Give it a fortnight. Mint’s keyboard settings can swap the two keys if your thumbs refuse.

Your Mac apps aren’t here, though most of what they did is. The list of what won’t work is written for Windows switchers and applies with one addition, which is that anything from the Mac App Store stays on the macOS side of the startup menu. Everything else about your first week is the same on a Mac as on a PC.