How to install Linux on an external SSD and use it via USB on any PC

Many people know about Linux Live USB drives, which let you boot a session with this operating system on any compatible computer.

What fewer people know or have considered is that you can carry a full Linux installation on an external SSD and boot your own system with your programs, files and settings.

And it is not the same as creating a persistent Live USB.

A persistent USB lets you save some changes, but the system still boots from a compressed Live image and writes modifications to a separate layer.

It is useful for trying Linux or carrying an emergency tool, but it is not the option I would choose for everyday use.

When you properly install Linux on an external SSD, it works almost like a normal installation:

• The performance is better, especially with an SSD and USB 3.0 or later.
• You can install programs without the usual limitations of a Live session.
• Your files and settings are saved directly on the system.
• You can update the system normally.
• It is less fragile than a persistence layer.

In other words, you can use the SSD as your little portable computer.

If you use two operating systems in your daily life—for example, Windows for leisure and Linux for work or crypto transactions—when you travel, having Linux installed on an SSD will save you from carrying two computers.

I set mine up for exactly that use case. Here is how I did it.

What you need

To prepare this, you need the following:

• An external SSD or one installed in a USB enclosure. Whether it is SATA or NVMe does not matter much.
• A USB flash drive of at least 4 GB, although 8 GB or more is better for the installation.
• The Linux ISO image. In my case it is Mint XFCE, but you can choose your favorite.
• A computer from which to perform the installation.

The USB flash drive will be used only as the installer. Linux Mint will be installed permanently on the external SSD.

Why I choose Linux Mint XFCE

Linux Mint has several editions:

• Cinnamon is the most visually complete.
• MATE is somewhat lighter.
• XFCE uses fewer resources and works better on modest computers.

I chose XFCE because I want to be able to use the SSD on both modern machines and older computers or those with less powerful processors.

It is not the most spectacular edition, but it is fast, stable and fairly easy to use. For me, as someone very used to Windows, the switch is quite straightforward.

You can download the Mint ISOs here.

Step-by-step guided tutorial

There are several steps, but they are simple.

#1. Check the SSD before installing

This step is optional, but recommended if the SSD is used, refurbished or from a little-known brand.

In Windows you can download and install for free CrystalDiskInfo and check:

• That the capacity is correct.
• That the health status appears as good.
• That there are no reallocated sectors.
• That the temperature is normal.

You can also use H2testw to write to and read the SSD's full capacity. 

This helps detect defective drives or units that advertise more capacity than they really have, and is especially advisable with cheap Chinese SSDs bought on AliExpress, like this one I bought for €12 (and it works well).

Warning: the test may take a while.

There is no need to delete anything that was written because we will format the drive later.

#2. Download Linux Mint XFCE

Download the Linux ISO you prefer. If you do as I did, you can download the Linux Mint images here.

The file will have a name similar to linuxmint-22.x-xfce-64bit.iso.

#3. Create the installer USB drive with Rufus

Download Rufus. It is a free program that will let us prepare the installation USB drive.

Connect the USB flash drive (not the SSD) and open Rufus in Windows.

Select:

• Device: the USB flash drive.
• Boot selection: the Linux Mint ISO.
• Partition scheme: GPT.
• Target system: UEFI.

Click Start and confirm that the USB drive will be erased.

When Rufus finishes, you will have a USB drive from which you can boot Linux Mint and install it on the external SSD.

Remember: do not write the ISO directly to the SSD where you want to install the system. We need two different devices:

• The USB flash drive contains the installer.
• Linux Mint is installed permanently on the external SSD.

#4. Disconnect the computer's internal drive

Shut down the computer completely and temporarily disconnect the internal SSD or hard drive (important).

On a desktop computer, removing the SATA data or power cable is usually enough. If you have an M.2 SSD, you will need to remove it or disable it in the BIOS if the motherboard offers that option.

On a laptop, you may need to open the bottom cover and temporarily remove the drive.

This step prevents two problems:

1. Accidentally erasing the drive that contains Windows.
2. The installer placing part of the Linux boot files on the internal drive's EFI partition.

We want the external SSD to be completely independent. Therefore, during installation, the computer should have only these devices connected:

• The installer USB flash drive.
• The external SSD.

If the internal drive remains connected, do not use the “Erase disk” option unless you are sure what you are doing, because you could select the wrong drive.

#5. Connect the USB flash drive and the external SSD

With the internal drive already disconnected, connect:

• The USB flash drive with Linux.
• The external SSD.

It is better to connect them directly to the computer, without hubs or extension cables.

Use a USB 3.0 port or faster for the SSD whenever possible. It is usually identified by its blue color, although not every manufacturer follows that convention.

#6. Boot from the USB flash drive

This step has two parts:

Step 1. Choose the boot device

Turn on the computer and enter the BIOS or open the boot menu. Either option works for what we need.

The key depends on the manufacturer, but it is normally one of these for BIOS access:

• F2.
• F10.
• Esc.
• Del.

Or, to access the boot menu:

• F12.
• F11.
• F9.
• Esc.

Select the USB flash drive entry that begins with UEFI.

Step 2. Choose the correct Linux option

When the Linux Mint menu appears, choose:

Start Linux Mint

Linux Mint will boot in Live mode and its desktop will appear.

Even if it sounds better, do not choose Install OEM, because that option is intended for manufacturers or shops preparing a computer for someone else.

#7. Check that the SSD appears

Before installing, open the Disks application from the Linux Mint menu. If you are using another Linux distro, open its equivalent application.

You should see:

• The installer USB flash drive.
• The external SSD.
• A virtual drive used by the Live system.

Identify the SSD by its brand, model and capacity. Do not rely only on names such as /dev/sda or /dev/sdb, because they can change from one computer to another.

If the SSD appears with the correct capacity, you can close the Disks application. You do not need to format it or create the partitions manually.

#8. Open the Linux Mint installer

Double-click the icon or look for the app in the main menu:

Install Linux Mint

Select English and continue.

The installer will ask for the keyboard layout. Choose “English (US)”, or the layout that matches your keyboard.

You will also see an option to install multimedia codecs. Depending on how you plan to use the computer, you can select it to have support for MP3, video and other formats from the start.

Normally, you should install them.

#9. Choose “Erase disk and install Linux Mint”

When you reach the Installation type screen, select:

Erase disk and install Linux Mint

This is the simplest option because the installer automatically takes care of:

• Creating a GPT partition table.
• Creating the EFI partition.
• Creating the main Linux partition in ext4.
• Configuring the swap file.
• Installing GRUB and the boot files.

You do not need to create an EFI partition manually or choose mount points.

The condition for doing this safely is that the internal drive is disconnected. At that point, the only disk available for installing Linux should be the external SSD.

Before continuing, check again the capacity and model shown by the installer. They must match your external SSD.

Click Install Now.

Linux Mint will display a warning explaining which disk it is going to erase and which partitions it will create.

Check that it mentions only the external SSD.

Any content on that SSD will be deleted completely. If it contains a file you want to keep, cancel the installation and make a backup before continuing.

If the indicated disk is correct, confirm the changes.

#10. Configure your user account

While the system installs, you will need to choose:

• Time zone.
• Name.
• Computer name.
• Username.
• Password.

You can enable automatic login, although requiring a password at startup is safer.

You may also see an option to encrypt the home folder. Encryption protects your data if someone steals the SSD, but makes recovery harder if you forget the password.

For an initial test, you can leave it unencrypted and later protect sensitive files with tools such as VeraCrypt or Cryptomator.

#11. Wait for the installation to finish

The installation can take anywhere from a few minutes to much longer, depending on:

• The speed of the USB flash drive.
• The speed of the SSD.
• The USB enclosure.
• The port used.
• The computer’s processing power.

Do not disconnect or move the SSD during the process.

When the message indicating that the installation has finished appears, click Restart Now.

#12. Remove the installer USB flash drive

When the computer shuts down or the installer asks you to:

1. Remove the USB flash drive.
2. Leave the external SSD connected.
3. Press Enter if a message appears asking you to continue.

When you turn the computer back on, if the SSD does not boot normally (it may well do so), open the boot menu again and select the external SSD.

Linux should start from the SSD.

The first boot may take a little longer than usual. After that, it should start more quickly.

#13. Test everything

Here we are going to make sure everything works as expected.

Step 1. Check that it works without the USB flash drive

Before reconnecting the internal drive, check that Linux Mint can boot with only the external SSD connected.

Open a few applications, restart and boot again from the SSD.

If it works correctly, that means the system, EFI partition and bootloader are all located on the external SSD.

That is the result we want. But there is one more test.

Step 2. Test the SSD on other computers

Connect the SSD to another computer, open its boot menu and select the USB drive.

When it starts, Linux should automatically detect the new computer's hardware:

• Processor.
• Graphics card.
• Sound card.
• Network adapter.
• Display.
• Keyboard and touchpad.

On reasonably standard UEFI computers, it should work without too many problems.

On certain PCs, although this is unusual, problems may appear with:

• Secure Boot.
• Especially restrictive UEFI firmware.
• Unusual Wi-Fi cards.
• Dedicated graphics cards.
• Computers that do not allow booting from USB.

Each case has a different fix, but on 99% of computers everything should work properly from the very first minute.

#14. Update Linux

Optional step, but recommended.

When the system is running, connect it to the Internet and open the Update Manager.

Install the available updates and restart when necessary.

You can also open the Driver Manager to check whether Linux Mint recommends any additional drivers.

Because the system will be used on several computers, it is better to avoid installing highly specific proprietary drivers unless you really need them.

#15. Reconnect the Windows drive

To finish, all that remains is to return the computer to its original state. Simply shut it down and reconnect its original internal drive.

From that point on, you can use both systems without creating a dual-boot setup:

• If you turn on the computer normally, Windows will start.
• When you want to use Linux Mint, open the boot menu and select the external SSD. Or configure the BIOS to try booting from USB first.

The two systems remain separate.

What performance can you expect?

Performance will mainly depend on:

• The speed of the SSD.
• The quality of the enclosure.
• The USB port.
• The computer you connect it to.

With a SATA SSD and a USB 3.0 enclosure, a relatively lightweight distro such as Linux Mint XFCE can run quite smoothly for the most common use cases:

• Browsing.
• Writing.
• Playing media.
• Working with documents.
• Programming.
• Using normal desktop applications.

It will also work over USB 2.0, but booting, updates and opening programs will be slower.

Conclusions

Installing Linux on an external SSD is almost the same as installing it on an internal drive, and the result is much more useful than a simple persistent live USB drive.

You carry your complete system, with your programs, files and settings, and can boot it on almost any compatible computer without touching the installed Windows system.

For me, that is the big advantage: using Linux when I need it without carrying a second laptop or setting up dual boot on every computer.

The key to the process is disconnecting the internal drive during installation. This prevents you from accidentally erasing Windows and ensures that both Linux and the boot partition remain on the external SSD.

After that, simply connect it, open the computer's boot menu and select the USB drive.

With a decent SSD, a USB 3.0 enclosure and a lightweight distribution such as Linux Mint XFCE, performance is more than sufficient for browsing, working, programming, playing media or carrying out normal desktop tasks.

In the end, what you carry in your pocket is not an installer or an emergency tool. It is your complete Linux computer, customized to your liking on an SSD and ready to work from any compatible machine.