[Solved] How to Clone Windows from MBR Disk to GPT Disk?

This tutorial explains how to clone Windows from an MBR disk to a GPT disk using Hasleo Backup Suite, including essential background knowledge.

 

Overview of MBR

As we know, the smallest addressable unit on a disk is a sector, and the sector size is typically 512 bytes. The Master Boot Record (MBR) refers to the first sector of a disk using the MBR partition scheme. This sector contains the boot code, disk signature, partition table, and end flag. Its detailed structure is as follows:

OffsetSize (bytes)Description
0x000440Boot code (flat binary executable code)
0x1B84Unique disk signature
0x1BC16First partition table entry
0x1CC16Second partition table entry
0x1DC16Third partition table entry
0x1EC16Fourth partition table entry
0x1FE2End flag(0x55, 0xAA)

As shown in the table, MBR supports a maximum of 4 primary partitions. To overcome this limitation when more partitions are needed, MBR uses an extended partition to describe more partitions (known as logical partitions). The partition information for each logical partition within an extended partition is stored in an Extended Boot Record (EBR). Consequently, a disk typically contains as many EBRs as logical partitions. Furthermore, the structure of each EBR is similar to that of a MBR. The overall structure of an extended partition is as follows:

extended partition

MBR uses partition table entries to describe the diak partitions. The structure of a partition table entry is as follows:

OffsetSize (bytes)Description
0x001Drive attributes (0x80: active partition)
0x013CHS Address of partition start
0x041Partition type
0x053CHS address of last partition sector
0x084LBA of partition start
0x0C4Number of sectors in partition

We can see that the partition table entry uses 4 bytes to describe the starting sector number and number of sectors of the partition, so MBR can only address disks up to 2 TB (2 ^ 32 x 512).

 

Overview of GPT

GUID partition table (GPT) is a part of the EFI standard that defines the partition table layout on a hard drive. In a GPT hard disk, the location information of the partition table is stored in the GPT header. For compatibility reasons, the first sector of the hard disk is still used as the MBR (usually called Protective MBR), and then the primary GPT header, primary partition table, partitions, backup partition table, and GPT header. Its detailed structure is as follows:

gpt partition cheme

Protective MBR: A GPT disk contains a partition table entry with type 0xEE in its Protective MBR, which is used to distinguish whether it is a GPT disk or a MBR disk.

Primary GPT header: The primary GPT header stores information such as the unique disk GUID (used to uniquely identify a GPT disk), CRC (cyclic redundancy check) of GPT header and partition table, the number of partition table entries, and the start LBA of the partition table entries array.

Partition table entry: It is used to describe a partition on the disk, including the partition GUID, start LBA and end LBA, as follows:

OffsetSize (bytes)Description
0x0016Partition type GUID
0x1016Unique partition GUID
0x208First LBA
0x288Last LBA
0x308Attribute flags (read-only, hidden, etc.)
0x3872Partition name

Backup partition table and GPT header: They are backups of the primary partition table and GPT header, used to restore GPT if the primary partition table or GPT header is lost or corrupted.

 

The advantages of GPT

Compared to the MBR partition scheme, the GPT partition scheme has more advantages.

MBRGPT
Maximum disk capacity2 TB9.4 ZB (9,400,000,000 TB)
Maximum partition capacity2 TB9.4 ZB (9,400,000,000 TB)
Maximum number of partitions4 primary partitions and several logical partitionsUnlimited number of primary partitions, Windows limits it to 128 partitions
Firmware boot supportBIOSUEFI
Data read or write supportAll Windows operating systems32-bit Windows Vista and later
64-bit Windows XP and later

✦ 1. GPT breaks the limitation of MBR on disk and partition capacity: GPT supports significantly larger partitions and disks, with a maximum capacity of 9.4ZB for each.

✦ 2. GPT can be used as boot disk for UEFI-based computers: Given that modern computers are primarily UEFI-based computers and MBR disks cannot be used as boot disks for UEFI-based computers, GPT is part of the UEFI standard. Therefore the use of GPT partitioning scheme is the future trend.

✦ 3. GPT partition scheme is more secure: The GPT header contains a CRC check that can be used to determine whether the GPT header and the partition table are damaged, and there are backups of the GPT header and the partition table, so if the primary GPT header or the partition table is lost or damaged, it can be restored from the backup.

✦ 4. Windows 11 can only be installed to a GPT disk: Since Windows 11, Microsoft has mandated that Windows 11 must be installed on UEFI computers, which means we have to use GPT to install and run Windows 11.

 

Tutorial to Clone Windows from MBR Disk to GPT Disk Using Hasleo Backup Suite

Step 1. Download, install and run Hasleo Backup Suite.

Download Best Free Windows Backup Software for Windows

Step 2. Click the "Clone" button in the navigation bar, then click "System clone" button in the operation area.

click system clone
 

Step 3. Hasleo Backup Suite will automatically select all partitions required for a Windows system clone. Simply click "Next" to proceed.

system clone select source disk
 

Step 4. Select the destination disk to which you want to clone the Windows OS. Tick the "Clone as GPT" option, then click "Next".

system clone select destination disk

Step 5. Adjust the partition size and location according to your needs, then click "Proceed". The system will pop up a warning message, prompting you that all data on the selected drive will be deleted. Please back up your important data in advance. If you have already backed up your data or do not wish to, click "Yes" to continue.

system clone adjust partitions

* Disk alignment:

  1. 1M (Recommended): 1M alignment is a subset of 4K alignment. Partitions aligned to 1MB are always 4K-aligned, which helps you get the best SSD performance. In Windows Vista and later operating systems, partitions created using Windows Disk Management are always aligned to 1MB bytes, regardless of whether the disk is an SSD.
  2. 4K: This option ensures the starting sector of every partition is aligned on a 4K bytes, which is very important for the best performance of an SSD.
  3. Cylinder: Ensure the starting sector of each destination partition always starts at the beginning of a cylinder. Windows XP and previous OSs use this alignment mode.
  4. None: The start sector of each the destination partitions is not aligned.

* The Sector by sector clone partiton option copies every sector from the source partition to the destination partition, including unused sectors.

Step 6. Hasleo Backup Suite is now cloning the Windows operating system to the target disk. The required time for this process depends on the size of data being cloned; please be patient.

disk clone progress

* Here you can specify a power management action to be performed after the backup is complete.

 

Frequently Asked Questions

Q: How do I clone Windows from MBR disk to GPT disk?

A: Run Hasleo Backup Suite, click Clone > System Clone, select the source MBR disk, choose the target GPT disk, tick the 'Clone as GPT' option, then click Proceed to start cloning.

Q: Why should I convert MBR to GPT for Windows 11?

A: Windows 11 requires UEFI boot, which mandates GPT partition scheme. MBR disks cannot be used as boot disks for UEFI-based computers, making GPT conversion essential for Windows 11 installation.

Q: What is the maximum disk size difference between MBR and GPT?

A: MBR supports a maximum disk size of 2TB, while GPT supports up to 9.4ZB (9,400,000,000 TB). This makes GPT essential for modern large-capacity storage devices.

Q: Can I clone MBR Windows to GPT without reinstalling?

A: Yes, Hasleo Backup Suite allows you to clone Windows from MBR disk to GPT disk without reinstalling. The cloned system will boot normally on the GPT disk with UEFI mode.

Q: Do I need to enable UEFI mode after cloning Windows to GPT?

A: Yes, after cloning Windows to a GPT disk, you must boot the computer in UEFI mode. You may need to change the boot order in BIOS/UEFI settings to boot from the new GPT disk.

Q: What are the advantages of GPT over MBR?

A: GPT offers several advantages: supports larger disks (up to 9.4ZB), allows unlimited partitions (Windows limits to 128), provides better data security with CRC checks and backup headers, and is required for UEFI boot and Windows 11.

Q: Will cloning MBR to GPT delete data on the target disk?

A: Yes, cloning will erase all data on the target GPT disk. It is essential to back up important data on the destination disk before proceeding with the cloning operation.

Q: Can I convert GPT back to MBR after cloning?

A: Yes, you can use Hasleo Backup Suite to clone Windows from GPT disk back to MBR disk if needed. Select 'Clone as MBR' option during the cloning process.

 

Conclusion

As mentioned above, with Hasleo Backup Suite, you can effortlessly clone Windows from an MBR disk to a GPT disk and guarantee that the Windows boots normally from the GPT disk.

As professional Windows backup and cloning software, Hasleo Backup Suite supports cloning Windows from an MBR disk to a GPT disk, restoring an MBR Windows system backup image to a GPT disk, or cloning Windows from a GPT disk to an MBR disk.

 

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