Why My Windows 8 Ready PC Won’t Boot From USB to Install Windows 7? And How To Fix It


I bought a Windows 8 pre-installed Lenovo ThinkPad that I want to downgrade to Windows 7. But when I tried to boot it from Windows 7 USB flash drive, I couldn’t get boot into it. It kept booting back to Windows 8, instead of starting the Windows 7 installation process. What was wrong?

Turned out, it’s because the secure boot is enabled to UEFI only that doesn’t allow any legacy system to boot up. If you want to downgrade your Windows 8 ready computer, you would have to disable the Secure Boot, and set the UEFI boot to allow both UEFI and Legacy systems.

On my ThinkPad in particular, I had to go into BIOS → Security, and disable Secure Boot there (Figure 1).

Figure 1 - disable Secure Boot in BIOS
Figure 1 – disable Secure Boot in BIOS

And go to Startup, to change the UEFI/Legacy Boot option to Both (Figure 2).

Figure 2 - select UEFI/Legacy Boot option to Both
Figure 2 – select UEFI/Legacy Boot option to Both

Once I’ve done that, I was able to boot into Windows 7 installation USB flash drive and start off the downgrading process.

UEFI, stands for Unified Extensible Firmware Interface, is a software middleware between an operating system and the platform firmware. It’s meant to completely replace the ancient BIOS firm interface but in practice it still provides the legacy support for BIOS services. Windows 8 is the first operating system that introduces the support to UEFI but it was caused quite a buzz when Microsoft announced it last year.


  1. Do not Disable SecureBoot. instead build your install media as FAT32. UEFI support FAT32 only and if you are using Microsoft USB build tool it format drive as NTFS.
    there is a tool called Rufus you can use. or simply format the drive in OS and copy files

  2. Thank you so much. All I wanted was Linux on my laptop dual-boot. 5 variations failed til I found one I could ‘install’. That installed but I couldn’t boot to it. I tried deleting bonus partitions (Failed) tried installing/mounting grub, 3rd party applications. All those failed too. I decided to go back to Win7 and now it blocks the boot usb tried building usb in FAT32 and NTFS both failed. Finally this and I wiped everything and installed 7. Soon I can install Linux. Thanks for the help!


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