Step-by-step guide to setting up dual boot on your PC or laptop

Are you tired of your operating system dictating what you can and can’t do with your PC or laptop? Need more control over your computing environment? Dual boot might be the answer. I have a dual-boot dream machine running both Windows 10 and Linux Mint 18. What I can’t do with one OS, I can do with the other.

You might have tried setting up a dual-boot, only to find that the second OS overwrote the first. The trick to successfully implementing dual boot is the order of events and using a dual-boot-friendly Linux distro.

This guide will walk you through the steps needed to set up a dual-boot system on your PC or laptop.

Select the operating systems

Linux Mint is a good option for the second OS. It is a popular distro with a start menu that is Windows-like, and its Cinnamon desktop user interface is clean and efficient. Most things you need are already packaged with the install (networking, email, browser, media player, office apps, etc.). Apps it doesn’t come with are easy to install with the Apps Manager or from the command prompt.

It really doesn’t matter what apps you use in Windows 10 or Linux; with a dual boot you can have it all. As a web developer managing a data center that’s almost 100% Windows/SQL Server-based, a full switch to Linux isn’t an option for me. I need a fully Windows-compliant local test environment.

On the other hand, I like to have full control over my file system, and that means knowing what’s on it, including hidden items that don’t display even when you tell them to, and system files, some of which never display in Windows. You can see all these files in Linux.

Ever get “access denied” when trying to delete a rogue file in Windows, even with administrator privileges? Just boot into Linux, find and delete the file. Is Windows 10 Internet browsing slowing you down? I’ve sometimes found navigating the Web to be faster in Linux. Each operating system has its own benefits, so why not take advantage of both?

First steps

Job one is to figure out if Windows currently boots into EFI system partition or into legacy mode. You can set up a dual boot in EFI, but this can get complicated. For this discussion I’m addressing legacy mode only, which can usually be enabled in your system BIOS.

However, don’t do anything until you make a recovery DVD and back up your data files separately so you can restore if something goes wrong. Don’t skip this step for any reason. I always proceed on the assumption that everything could get nuked, so I always have a full backup of all the files I wish to keep. In fact, in the process of setting up the environment for this article I accidentally overwrote the Master Boot Record (MBR), so be forewarned.

Back to install prep -- you already separate your programs from your data, right? If not, I highly recommend this, because when (not if) you eventually need to reinstall the operating system, your data, having been stored on a separate partition, won’t be affected.

With this scenario you need three partitions, one for Windows, one for data and one for Linux. There are multiple ways to do this, but your first choice should be trying it in Windows.

Assuming you have enough drive space, shrink your C partition and then create a D partition to hold your data. If the letter D is already in use by your CD-ROM drive, assign a different letter to that drive before proceeding; I always use X to keep it out of the way. I usually keep my C partition to no more than 30% of my total drive space, because in my case apps take up much less space than data.

When installing or reinstalling, especially with more than one OS, the identifiable “C: D: E:” drive lettering system either goes away or gets switched around, but partition names remain intact. I always name the D: drive ‘DATA’ so I can see it when reinstalling and this keeps me from accidentally installing the OS over my data.

Next, shrink the D: partition so you end up with at least 30GB for Linux. It will install in less, but I’ve found this to be a serviceable size for a utility installation, with a bit of room for expansion. I name the Linux partition LINUX, but you can leave it unnamed. You don’t need to know how to create Linux partitions.

Here’s what the partitions look like from Windows 10 Computer Management.

If for some reason partitioning doesn’t work from Windows, you can do it from a Windows install medium (CD/DVD or flash drive). You have to choose a full install, not a refresh. This will give you the chance to partition drives before installing Windows.

If neither of these methods works, you’ll need the nuclear option, using Linux from a bootable medium (DVD or flash drive) to create new partitions. There are multiple ways to do this, but I like to use a USB-bootable Linux with the program GPARTED installed. GPARTED gives you a graphical view of your drives and lets you make changes in graphics mode.

Just remember to commit your changes by clicking the green arrow, otherwise nothing will be saved. If you create new partitions by first deleting old ones, your data will definitely be overwritten (not literally, but you’ll need a disk forensics expert to recover it) so backup everything first or try out the dual boot on a test box.

If you have to create new partitions and Windows is no longer bootable, install Windows next, before installing Linux. This is important in the order of events. If you install Windows after Linux, Windows will overwrite the MBR and your Linux partition will be stranded and unbootable. Make sure Windows boots as it should before proceeding to the next step.

Don’t bother to activate or set up Windows at this point. Just make sure it boots and is installed to the correct partition. Hold off copying your data back to the D: drive. You want to make sure the dual boot succeeds before spending time on configuration.

With Windows installed and bootable, and your other two partitions (DATA and LINUX) ready to go, it’s time to install Linux Mint. If you haven’t done so already, download the Linux Mint live ISO image. For Windows users just starting to evaluate Linux, I recommend the Cinnamon desktop version, which looks and behaves similarly to Windows 7. Burn the ISO (about 1.6 GB) to a DVD and then boot to it. Alternatively you can make a bootable USB flash drive by using this handy little utility.

Linux Mint boots up to a live version that runs in memory. To start the dual boot installation, select the Install image from the desktop.

This launches the wizard that guides you through the installation process including the option to ‘Install Linux Mint alongside Windows 10.’

Be careful not to select the ‘Erase disk’ option because the installer will do exactly that and everything that is on your hard drive will be overwritten by Linux.

It takes a bit of flying blind to perform the next step, but just remember the Linux installer won’t overwrite your Windows installation or your data if you’ve performed the steps above. The Linux installer looks for the next block of unused space and it will display a popup asking you to confirm its proposed plan to create (usually two) Linux partitions in the unused space. This is the last point where you can bail before changes are written to your hard drive. When ready to proceed, just accept the defaults and the wizard will continue the install, during which it displays various screens showing the features of Linux Mint.

So the install is now complete, but how do you dual boot? Behind the scenes during the install, Linux Mint automatically creates a GRUB (Grand Unified Bootloader) that your system will display the next time it boots. This allows you to choose either Windows 10 or Linux, although Linux is the default. Voila, you’re all set with the dual boot.

Although it’s beyond the scope of this discussion to review the many features of Linux Mint, you will find numerous resources online including an active community forum. I find Linux Mint to be pretty intuitive for Windows users from the get-go, just by navigating the self-explanatory menus.

In case you’re not quite ready to commit to a dual boot, there is a simpler way to evaluate Linux Mint on your system. Just boot to the live distro, either by DVD or bootable USB drive (see instructions earlier in this article). Nothing is written to your hard drive and you can explore the features of the OS, which is contained in volatile memory and erased once you reboot without the ISO.

Perschke is a web and database developer with 15+ years of industry experience. You can reach her at susan@arcseven.com.

This story, "Step-by-step guide to setting up dual boot on your PC or laptop" was originally published by Network World.