The only true and reliable way to go form Legacy boot to UEFI is to backup all your files, make the necessary changes in BIOS to switch to UEFI, then format your drive and change the partition style to GPT, and clean install Windows 10 and all your software . 64-bit UEFI PC can only boot 64-bit version of Windows 10, while 32-bit UEFI PC can boot 32-bit OS only. zbook said: This may be another option: 1) Create a Windows.old 2) Change the BIOS from UEFI to Legacy 3) Clean install Windows 10 20H2 4) Restore Windows.old its got a windows.old What worked, however, was UEFI. But almost all of them have a fallback mode which allows the hardware to be configured in the legacy mode called BIOS mode.Here is how you can tell which mode exactly is used on your Windows 10 PC. The UEFI BIOS has replaced the old BIOS which we now refer to as Legacy BIOS. But, if you have an older PC to start with, there are a lot of reasons for you to seek for the Legacy boot process. There’s quite a bit of difference between the two if you’re a desktop/laptop/computer component manufacturer. How to Put Windows 10 on a USB Drive via ISO with Rufus (Legacy or UEFI) The in-built Windows 10 download tool is good enough, but there are some instances where you might want to … Many modern PCs run the installed OS in UEFI mode. The procedure to change from Legacy BIOS to UEFI depends on your motherboard manufacturer. If you have the Windows 10 ISO image on your PC, you can choose to make a Windows 10 bootable USB drive with UEFI or legacy bootloader. How to Create UEFI or Legacy Bootable USB Drive for Windows 10 Setup. . jebediah said: To boot from USB i had to switch from UEFI to Legacy, otherwise the USB drive would not be listed. As we all know now, Windows 10 PCs come with default UEFI settings these days. 5. Changing from Legacy Bios to UEFI, settings in bios and Windows 10 in Installation and Upgrade I used the Windows converting program MBR2GPT.exe to convert my SSD to GPT and it reported it had done it. For end-users, the difference is that UEFI BIOS is more secure. RAM: 8GB. Consult the manual for the exact steps. If you don't have access to the Windows 10 desktop or you're using a device with a legacy BIOS, then you can still access the firmware during boot. Processor: i5-6300U CPU, dual core. Now restart your system, launch your motherboard firmware settings screen and change it from Legacy BIOS to UEFI. So, it is quite obvious that Legacy or BIOS-compatible modes are not our first choice. . Depending how the Windows 10 install media is booted (UEFI or Legacy BIOS) Windows Setup creates either GPT or MBR partition style on the hard drive. The problem is following: Legacy mode suddenly stopped booting the computer, saying that hard drive is not found. Anyway a little reading will clear some myths posted around the net. BIOS: Windows 10 Pro. I myself use UEFI since I've nothing that requires legacy. After booting into Windows 10, you can verify whether you are converted or not. From there you can make up your mind. Hard drive: Toshiba THNSNK256GVN8 M.2 2280 256GB SSD. Laptop: Dell Latitude E7470 x64. 6. Good luck. If you have new hardware and use Windows 10, UEFI is the way to go. UEFI also boots faster than legacy.