How to change or convert mbr to gpt without data loss?

Converting a disk from Master Boot Record (MBR) to GUID Partition Table (GPT) without data loss is a common necessity, especially for upgrading to newer operating systems like Windows 11 or utilizing large drives (over 2TB).

Regardless of the MBR to GPT conversion method used, always back up all critical data before attempting any disk partition style conversion. While MBR2GPT and certain third-party tools are designed to be non-destructive, any operation involving the partition table carries a small risk of data loss.

For Windows system disk conversion, the official Microsoft tool, MBR2GPT.exe, is the safest and most standard choice, provided your disk layout meets the requirements (e.g., no logical partitions and running Windows 10 version 1703 or later).

MBR2GPT.exe Limitations (Cons)

System Disk Only: The tool is designed exclusively to convert the system (OS) disk that holds the operating system. It cannot be used to convert data-only disks from MBR to GPT.

Maximum 3 Primary Partitions: The MBR disk to be converted must have 3 or fewer primary partitions.

No Extended/Logical Partitions: The disk must not contain any Extended or Logical partitions. The tool is incompatible with this MBR partitioning scheme.

Requires BIOS to UEFI Conversion: The MBR2GPT tool only converts the partition style on the disk. For the computer to boot, you must manually change the firmware (BIOS) settings from Legacy/CSM to UEFI Mode after the conversion is complete. Failure to do this will result in a non-bootable system.