https://answers.microsoft.com/en-us/windows/forum/all/convert-an-existing-windows-10-installation-from/aa8c2de3-460b-4a8c-b30b-641405f800d7
Step 4: Change the boot order in firmware Settings. Now to boot from GPT, the settings in the firmware need to be changed. Boot to the PC's firmware settings, and do the following: Boot method: UEFI from Legacy. UEFI-CSM: Disabled. Secure Boot: ON. The boot order would usually show Windows Boot Manager at the top.

https://www.thewindowsclub.com/how-to-change-legacy-to-uefi-without-reinstalling-windows-10
Run Command Prompt as Administrator and execute the following commands one after the other: mbr2gpt.exe /convert. Wait until the process is complete. When it is done, you need to go to the BIOS of

https://www.tenforums.com/tutorials/81502-convert-windows-10-legacy-bios-uefi-without-data-loss.html
1 Open a command prompt at boot. 2 Copy and paste the mbr2gpt /convert command into the command prompt at boot, and press Enter. (see screenshot below) 3 When the conversion has successfully completed, you will need to boot to UEFI firmware settings, and switch the firmware to boot to UEFI mode instead of Legacy BIOS (CSM).

https://www.wintips.org/how-to-change-legacy-to-uefi-without-reinstall-windows-10/
How to use MBR2GPT.EXE tool, to convert MBR partition to GPT, without data loss. Once again: The instructions below apply only if you have already Windows 10 version 1703 or later on your system. If you don't, then navigate to Windows 10 download site and click the Update now button, to install the latest Windows 10 version.. Suggestion: Before you continue to the steps below, backup your data

https://www.thewindowsclub.com/convert-mbr-to-gpt-disk
1. Convert MBR to GPT using Diskpart. Backup all your data and then use the DISKPART command. Open command prompt, type DISKPART, and press Enter. Then type in list disk (Note down the number of

https://www.windowscentral.com/how-convert-mbr-disk-gpt-move-bios-uefi-windows-10
To convert a drive using MBR to GPT on Windows 10, use these steps: Open Settings. Click on Update & Security. Click on Recovery. Under the "Advanced startup" section, click the Restart now button

https://www.diskpart.com/windows-10/convert-windows-10-from-legacy-bios-to-uefi-without-data-loss-7201.html
3. Click on "Apply" to commit the pending operation. Then the computer will finish the operation in Win PreOS mode. Step 2. Convert Windows 10 from Legacy BIOS to UEFI. After you have converted the Windows 10 system disk from MBR to GPT, now need to reboot the system, boot into BIOS and select UEFI firmware.

https://beebom.com/convert-mbr-gpt-windows-10/
4. Here, switch to the " Volumes " tab and look for the "Partition style". If it's MBR, we indeed need to convert the MBR partition to GPT. And if it displays GPT, we don't need to do anything. 5. Next, press the Windows key once and search for " System information ". Open it. 6.

https://www.makeuseof.com/tag/convert-mbr-gpt-windows/
Purchase the software, download, and install. ( Tip: If you're only converting one drive, grab the Trial version.) Open EaseUS Partition Master and wait for your drives to load. Next, locate the drive you want to convert. Select the disk, right-click, and select Convert MBR to GPT . Press the Apply button on the toolbar.

https://www.minitool.com/partition-disk/convert-legacy-to-uefi.html
Here is the guide: Step 1: Create a Windows 10 or Windows 11 installation media. Insert the media to your PC and make the PC boot from the media. Step 2: Go on until you see the Install now window. Then, click Repair your computer button in the bottom left corner. Go to Troubleshoot > Command Prompt.

https://www.youtube.com/watch?v=ZvlWJX3IXFY
In this video guide I will show you to change or convert the windows boot from MBR to GPT or Legacy to UEFI with only one line in command prompt or CMD.This

https://www.intel.com/content/www/us/en/support/articles/000024558/memory-and-storage/intel-optane-memory.html
Open Command Prompt with administrator privileges. Run the following command: mbr2gpt.exe /convert /allowfullOS. Restart the system and boot into the system BIOS. Change the settings from Legacy BIOS mode to UEFI mode. Alternatively, you may also run this command from the Windows Recovery Environment: Boot into the Windows Recovery Environment.

https://www.tenforums.com/tutorials/81502-convert-windows-10-legacy-bios-uefi-without-data-loss-13.html
From a command prompt in the Macrium Free rescue drive it would be: diskpart. select disk 0 <- assuming the SSD is drive 0. You can run the list disk command to make sure. clean. convert mbr <- probably unnecessary as the clean command automatically sets it to MBR. exit. exit. Then restore the image to the SSD.

https://www.easeus.com/partition-manager-software/convert-mbr-to-gpt-without-reinstalling-windows.html
Launch EaseUS Partition Master, go to the Disk Conversion section, select "Convert to GPT" and click "Next". Select the OS MBR disk as the target disk, and select "Convert". Once done, reboot PC and change the boot mode from Legacy BIOS to UEFI. Seve the changes and reboot the PC. 2.

https://www.diskpart.com/articles/convert-mbr-to-uefi-1984.html
Right-click the system disk and select "Convert to GPT". Step 2. Ensure you have converted Legacy BIOS to UEFI, and click "Yes" to confirm. Step 3. In the main interface of AOMEI Partition Assistant, click "Apply" to start the conversion. And wait for the operation to complete.

https://www.itechtics.com/mbr-to-gpt/
Open the Run dialog (Windows key + R) and type diskmgmt.msc. This will open the Disk Management console. Select the disk you want to convert and then go to Actions menu -> All tasks -> Convert to GPT. This will convert MBR to GPT. Please note that if your disk is already GPT, you will get an option to convert GPT to MBR.

https://www.youtube.com/watch?v=v19bZdxrEz8
How to Convert Legacy to UEFI (Without Losing Data) | Change MBR to GPTCheck these 2 methods through which you can change your BIOS mode from legacy to UEFI

https://superuser.com/questions/1200263/how-can-i-migrate-a-windows-10-from-bios-mbr-boot-to-uefi-gpt-without-reinstalli
Now look or the disk number where your Windows is installed. This number is important for next step. Now run mbr2gpt /convert /disk:ID with the ID: X:\>mbr2gpt /convert /disk:0. MBR2GPT will now attempt to convert disk 0. If conversion is successful the disk can only be booted in GPT mode. These changes cannot be undone!

https://www.tenforums.com/tutorials/81502-convert-windows-10-legacy-bios-uefi-without-data-loss-22.html
Then boot the computer from the Macrium Rescue Drive, wipe disk 0. Convert it GPT. Create an EFI System Partition (100 mb), restore the C: drive image to the rest of the drive. Run the fix windows boot problems utility from the Macrium Reflect restore menu.

https://superuser.com/questions/1677802/convert-from-mbr-to-gpt-without-data-loss-and-no-windows
Now just run mbr2gpt to do the conversion, for example the below will convert disk 0 to GPT. MBR2GPT.EXE /convert /disk:0 /allowfullos. As long as your disk satisfies the requirements, it'll convert the disk from MBR to GPT without data loss. See also Convert MBR to GPT - Without any OS. If it fails to convert then see Cannot convert from MBR

https://www.youtube.com/watch?v=sT6YEOgGuBc
This video will show you steps to convert Windows 10 Installation from Legacy BIOS to UEFI without using any third party software.If you get MBR2GPT disk lay

https://www.tenforums.com/tutorials/81502-convert-windows-10-legacy-bios-uefi-without-data-loss-11.html
Brink said: I noticed that your "Active" partition is on Disk 1 instead of Disk 0. As a test, disconnect Disk 1, 2, and 3 leaving only Disk 0 connected to see if you're still able to boot into Windows 10 and convert to UEFI. If you can't boot, then you could see if running a Startup Repair may allow you to afterwards.

https://www.msn.com/en-us/news/technology/how-to-convert-ssd-from-mbr-to-gpt-a-step-by-step-guide/ar-AA1lHADJ
Master Boot Record (MBR) and GUID Partition Table (GPT) are two partitioning schemes used for SSDs and HDDs.MBR, an older standard, works well with legacy BIOS firmware on older computers, whereas

https://www.tenforums.com/tutorials/81502-convert-windows-10-legacy-bios-uefi-without-data-loss-26.html
Pretty sure I posted screenshots on here somewhere. Expand the C: partition using unallocated space, then defragment the c: drive, then reduce the C: drive by 2 GB and try mbr2gpt again. Maybe there's too much disk fragmentation right now causing the failure - I'm speculating.