Two operating systems on one PC, and you pick which one starts — that is dual boot. This page writes down the complete safe method from the video: prepare Windows first, install Ubuntu alongside it, and finish with a working GRUB menu. Windows and all your files stay exactly where they are.
Dual booting simply means Windows and Ubuntu live side by side on the same disk, and every time you start the PC a menu asks which one to load. Nothing runs at the same time — you restart to switch. The video above shows the whole job live. This page is the same method in writing, in the safe order: Windows is prepared first (backup, BitLocker key, shrink, Fast Startup off), then Ubuntu is installed into the space you freed. Follow the order — most dual boot disasters come from doing the steps backwards.
The shopping list is short and everything on it is free. Download the Ubuntu ISO (the LTS version) from ubuntu.com, and keep a USB pen drive of 8 GB or more ready — it will be fully erased while making it bootable, so copy anything precious off it first.
That backup is not decoration. Partition work is safe when done in the right order, but a power cut or a wrong click in the middle of it can cost real data — until the backup exists, the risk is real and no guide can remove it.
All preparation happens inside Windows, before the USB is even created. First, shrink the Windows partition to make room. Windows itself is the safest tool for shrinking its own partition.
diskmgmt.msc and press EnterNext, if your Windows is protected with BitLocker (common on modern laptops), find and save the recovery key now — from your Microsoft account devices page or with manage-bde -protectors -get C: in an admin Command Prompt — and suspend BitLocker protection until the install is done. Changing boot and partition settings can make Windows demand that key, and without it you are locked out of your own drive. Finally, turn off Fast Startup in Control Panel power options — with it on, Windows never truly shuts down, and Ubuntu sees its drives as locked. Both of these preparation steps have their own full guides in this series.
Now turn the pen drive into the Ubuntu installer. Two free tools do this well, and both are shown across the channel — Rufus writes one ISO to the drive the classic way, while Ventoy lets you keep several ISOs on one pen drive and pick at boot time.
That is all. The drive now boots into the Ubuntu installer on almost any PC. Keep the Windows preparation from the last step in mind — the USB is the easy half of this job; the Windows side was the important half.
Restart the PC and open its one-time boot menu — usually by tapping F12, F8 or Esc during startup, depending on the brand — and choose the USB drive. On a modern PC, pick the entry that says UEFI next to the drive name. Try Ubuntu for a minute to confirm the keyboard, Wi-Fi and display behave, then start the installer.
The alongside option is the whole secret of the easy method: the installer finds the empty space itself, builds its partitions there, and adds Windows to the boot menu automatically. The manual Something else route exists for custom layouts, but a first dual boot does not need it.
Documents, music and other personal files will be kept. You can choose which operating system you want each time the computer starts up.
One rule decides whether the boot menu can see both systems: Windows and Ubuntu must be installed in the same boot mode. Modern Windows 10 and 11 machines run in UEFI mode on a GPT disk, and the Ubuntu USB must be booted in UEFI mode too — that is why the last step told you to pick the UEFI entry for the pen drive.
msinfo32 in Windows and read the BIOS Mode lineMixing modes — Windows in UEFI, Ubuntu installed in legacy mode, or the reverse — is the classic reason one system simply never appears in any menu. Same mode, no problem.
Restart after the installation and the GRUB menu from the top of this page should greet you. Ubuntu is the default entry and starts on its own after a short countdown; use the arrow keys to pick Windows Boot Manager whenever you want Windows. Both systems are now fully installed — test each one once before calling the job done.
Two small things people meet in the first week: the menu may later disappear after a Windows update, and the clock may show the wrong time in Windows. Both are one-setting fixes, and both have their own pages in this series — the dual boot itself is complete.
The complete installation from the video — ISO download, bootable USB, partition shrink and the GRUB menu, shown live step by step.
▶️ Watch Full VideoNo, not when it is done in this order. You free the space from inside Windows first, and the Ubuntu installer uses only that empty space with the alongside option. Windows, your programs and your files are not touched. The one real danger is clicking the erase disk option or picking the wrong partition, which is why a backup comes before everything.
The Ubuntu installer asks for roughly 25 GB as a minimum, but that fills quickly once you install programs and updates. Give it 40 to 60 GB if your drive allows it. Ubuntu itself is light — the space is for your files and software, and growing the partition later is far more painful than choosing generously now.
Yes, completely. Set Windows Boot Manager first in the boot order, delete the Ubuntu entry from the EFI partition, delete the Ubuntu partitions in Windows Disk Management and extend the C drive back into the freed space. The removal guide in this series walks through that order step by step, so Windows boots exactly as it did before.