The most common reason a Rufus USB refuses to boot is not a bad download - it is this one dropdown. Partition scheme has to match how the target PC's firmware boots, and this page shows you how to find that out in ten seconds.
Rufus sets the Target system line automatically from this choice, which is your first clue that the two belong together: GPT pairs with UEFI, MBR pairs with BIOS. Pick by the target machine's firmware and the rest of the creation process is uneventful.
Forget the USB for a moment - this setting describes the PC that will boot from it.
If the target PC still starts into Windows, you can read its boot mode directly:
msinfo32 and press Enter.No working Windows on it? Enter the firmware setup (usually Del, F2 or F10 at power-on) and look for UEFI or Legacy/CSM settings. A board with a graphical, mouse-driven setup screen is UEFI.
GPT is the modern pairing and the one Windows 11 expects: Secure Boot works in this mode, the firmware hands over to the installer quickly, and the installed system can boot from disks larger than 2 TB. If the PC supports UEFI, there is no advantage in choosing MBR - you are only adding a translation layer the PC does not need.
MBR exists for machines that predate UEFI, and for a shrinking set of stubborn cases: very old laptops, BIOS-only boards, and a few early UEFI boards whose firmware handles boot media badly. There is also a practical quirk worth knowing - an MBR stick will boot on many UEFI PCs too, if their CSM (legacy support) mode is switched on. That is why one old MBR stick seems to work everywhere. But on a strict UEFI machine with Secure Boot enforced, that same stick may not appear in the boot menu at all.
The classic failure: a GPT stick plugged into a PC forced into Legacy mode, or an MBR stick on a Secure-Boot-only PC. The USB simply does not appear in the boot menu, and the drive gets blamed. Nothing is broken. Recreate the stick with the matching scheme - it takes a few minutes and touches nothing on the PC's internal disk.
See the partition scheme get picked live in the video, with the target system line changing alongside it.
▶️ Watch Full VideoNo. The scheme is the partition table of the drive itself, so Rufus has to rewrite the drive. The good news is that a rewrite takes only a few minutes, and nothing on any PC's internal disk is affected.
Because your firmware's CSM or legacy support was enabled, so the UEFI board also accepted the old-style boot. That is normal behaviour. The reverse is not true - a strict Secure Boot UEFI setup will ignore media it cannot verify, which is usually an MBR stick.
GPT, with the PC in UEFI mode. Windows cannot boot from a disk over 2 TB in MBR mode, so for big modern drives the question answers itself - GPT installer, GPT system disk.