To switch from Legacy BIOS to UEFI, you’ll typically need to adjust both the firmware settings and the partitioning scheme of your system drive. Here’s a practical, step-by-step guide you can follow. Note: making these changes can affect your operating system booting, so proceed carefully and back up important data first. Direct steps
- Check current boot mode
- In Windows: open System Information (type msinfo32 in Start), look for “BIOS Mode.” If it says Legacy, you’re in Legacy BIOS mode; if it says UEFI, you’re already in UEFI. This helps confirm what needs to be changed. [citation context not shown here]
- Prepare Windows for UEFI (MBR2GPT path) if your disk is MBR
- Windows includes a tool called MBR2GPT that can convert a system disk from MBR to GPT without data loss under certain conditions.
- Important requirements:
- Windows 10 version 1703 or later (ideally updated)
- The disk must be basic, online, with a single partition layout suitable for conversion
- There should be enough free space on the disk for the conversion process
- Typical commands (run in an elevated Command Prompt or Windows PowerShell):
- Validate: mbr2gpt /validate /allow32bit /disk:0 /partitions:1-4
- Convert: mbr2gpt /convert /allow32bit /disk:0 /partitions:1-4
- After a successful conversion, you’ll need to enable UEFI boot mode in the firmware.
- Enable UEFI boot in the firmware
- Reboot and enter the firmware/BIOS setup (common keys: Del, F2, Esc, or a manufacturer-specific key shown on screen during startup).
- Locate boot options and switch the boot mode from Legacy to UEFI. Some systems also require disabling Compatibility Support Module (CSM) or Legacy Boot, and enabling Secure Boot (optional, but recommended after setup).
- Save changes and exit, allowing Windows to boot in UEFI mode.
- Verify the change
- In Windows, open System Information again and verify that “BIOS Mode” shows UEFI.
- You may also verify GPT partition style by using Disk Management or diskpart commands:
- Open Command Prompt as administrator and run: diskpart -> list disk -> select disk 0 -> convert gpt (only if you converted; otherwise you’ll see the current layout).
Manufacturer-specific notes
- Many brands provide a straightforward path:
- Dell, Lenovo, HP, Asus, and others typically use a BIOS/UEFI menu with a “Boot” or “Security” section where you can enable UEFI and disable Legacy/CSM.
- If you’re dual-booting or using Windows, ensure that Windows Boot Manager is the first boot option after enabling UEFI.
Common pitfalls and tips
- Backup is essential. Converting from MBR to GPT and switching boot modes can be risky.
- If Windows is installed in Legacy mode on an MBR disk, you must convert to GPT and switch to UEFI; otherwise, Windows may fail to boot.
- Secure Boot considerations: enabling Secure Boot after you’ve confirmed a working UEFI boot is typical, but some older hardware or operating systems may require disabling Secure Boot temporarily.
- Some systems may require a firmware update before they support full UEFI boot with GPT/Windows for certain configurations.
What I can tailor for you
- If you tell the exact computer model or motherboard, the current OS version, and whether the disk is MBR or GPT, a precise sequence of steps and the exact menu names for that model can be provided.
- If you have data on the drive you’re concerned about, I can walk you through a safer plan with a verified backup strategy and a rollback plan in case something goes awry.
