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The mobo supports uefi and from what I read it automatically switch to uefi when csm is disabled
The mobo supports uefi and from what I read it automatically switch to uefi when csm is disabled
Well on my board I have it Enabled and it gives me 3 choices, UEFI & Legacy Boot, Legacy, or UEFI
I leave it at the 1st option.
If I disable it, it doesn`t list any Boot options.
You are going to have to fix it from another os or boot media.
What have you got in that department?
Years ago, I used Linux Mint to convert the system disk from MBR to GPT without data loss and then clean installed Windows 10 in UEFI mode after deleting only Windows partitions without touching the data partition, drive D.
I have been using H81M too.
My CSM is enabled although I use UEFI.
Ya I think it has to be Enabled or there`s no list of boot choices, I just tried it.
Just leave it at UEFI & Legacy OPROM and you`ll never need to change it.
The only change you`ll have to make is OS Type, from Other OS, to Windows UEFI Mode, under Secure Boot which has to be Enabled.
Oh and here is something I remember from using the MBR2GPT /convert /allowFullOS command on the X299
I had to use my Macrium Rescue USB stick to repair the Boot record.
Last edited by AddRAM; 06 Oct 2021 at 02:17.
@TheViper,
If you have a Windows 10 installation USB flash drive you can boot the computer from, at the first screen press Shift + F10 to open a command prompt. Or use any other way to get to a command prompt, such as booting from a Macrium Reflect or other rescue type USB flash drive.
I am assuming you have a single drive in the computer. Run:
Do you see a small system partition listed, like my 100 mb System partition?Code:diskpart list disk select disk 0 <-0 should be your main drive, if it isn't, change the number to match your main drive list part
Code:Microsoft Windows [Version 10.0.22000.194] (c) Microsoft Corporation. All rights reserved. C:\WINDOWS\system32>diskpart Microsoft DiskPart version 10.0.22000.1 Copyright (C) Microsoft Corporation. On computer: JOHN-LAPTOP DISKPART> list disk Disk ### Status Size Free Dyn Gpt -------- ------------- ------- ------- --- --- Disk 0 Online 476 GB 588 MB * Disk 1 Online 476 GB 2048 KB * DISKPART> select disk 0 Disk 0 is now the selected disk. DISKPART> list part Partition ### Type Size Offset ------------- ---------------- ------- ------- Partition 1 System 100 MB 1024 KB Partition 2 Reserved 16 MB 101 MB Partition 3 Primary 347 GB 117 MB Partition 4 Primary 128 GB 348 GB DISKPART>
You have converted your drive from MBR to GPT but it didn't created the EFI - Fat32 100M partition that has the boot manager to boot as UEFI-GPT.
You don't need to reinstall Windows
You must create a EFI - Fat32 100M partition and load a boot manager on it.
The MBR System partition can be converted to EFI - Fat32 100M partition.
Follow NavyLCDR instructions and you will have your computer booting as UEFI-GPT
Thanks for all the answers, I will have the USB ready tomorrow because I don't have a pc to burn the iso so I will use a friend's pc to burn it
@Megahertz
How do I create the EFI partition? NavyLCDR instructions only shows how to check if I have the partition or not how to create it and load boot manager on it
The first step is to find out your drive layout
Boot from a a Windows 10 installation USB flash drive and at the first screen press Shift + F10 to open a command prompt. Type the code below:
Once you find out the the drive number, the System partition number and Windows partition number then we can give you the instructions to format it to Fat32 and to load it with the boot manager.Code:diskpart list disk (take note of your drive number n) select disk n (change n with the drive number you found above) list part (It will list all the drive partitions. Take note of your System partition number x and Windows partition number z)
Last edited by Megahertz; 06 Oct 2021 at 15:59.