How can I change mbr to gpt without data loss?

Changing a disk from MBR to GPT without data loss is possible using certain tools and methods, but it carries some risks. Before proceeding, it's highly recommended to back up your important data to prevent any accidental loss.

Methods to change MBR to GPT without data loss:
1. Use Microsoft's MBR2GPT Tool (Built-in Windows 10/11)
Microsoft provides a free tool called MBR2GPT that can convert a disk from MBR to GPT without deleting data. This tool is available in Windows 10 version 1703 and later.

Prerequisites:

• The disk is the system disk (boot disk).
• The disk has enough space and a compatible partition layout.
• You have a recent backup, just in case.

Steps:
1. Open Command Prompt as Administrator:
Press Windows + X → select Command Prompt (Admin) or Windows PowerShell (Admin).

2. Validate the disk:
Run: mbr2gpt /validate /disk:<disk_number> /allowFullOS
Replace <disk_number> with the correct disk number (usually 0 for the main disk). You can find it using diskpart:
diskpart
list disk
exit

3. Convert the disk:
Run: mbr2gpt /convert /disk:<disk_number> /allowFullOS

4. Reboot your PC:
After conversion, restart your PC and enter BIOS/UEFI.
Change the firmware mode from Legacy BIOS to UEFI if needed.

Note: If your system is using BIOS mode, you'll need to switch to UEFI mode after conversion.