Windows

How to Convert MBR to GPT Without Losing Data in Windows

How many hard drives does your system have? One? Three? Ten? Regardless of how many drives you have, they all need one thing to keep track of what’s on the drive: a partition table.

The partition table describes the partitions (sections) of the drive and helps your system find the files you need.

Your Windows system uses a master boot record (MBR) or GUID Partition Table (GPT) depending on the age, operating system, and your system firmware. Sometimes it is necessary to switch between MBR and GPT but to do that you need to wipe your drive first. Using traditional tools like Windows Disk Management and the Command Prompt results in permanent data loss (unless you back up, of course!).

But now there are two tools you can use to change your partition table without suffering any data loss safely. And the best part is how supremely easy it is (as well as entirely free). Let’s take a look at how you can convert your MBR disk to GPT—without losing a scrap of data.

MBR to GPT

MBR vs. GPT

First up, consider the differences between MBR and GPT, and why some systems use one over the other.

MBR

MBR is the more established of the two and is so compatible with a wider variety of systems. MBR was developed for IBM PCs and was, for a long period of time, the dominant partition table choice for Windows machines. The Master Boot Record gets its name from its location at the drive’s beginning; it contains the operating system’s bootloader and information about the drive’s partitions.
MBR is only compatible with drives up to 2TB in capacity. Additionally, an MBR disc is limited to four primary partitions. This was acceptable when a 2TB drive was a major investment, but an 8TB drive, such as a Seagate Barracuda, is now reasonably priced.

GPT

GPT is the more recent addition to the two. GPT is inextricably linked to UEFI, the firmware solution that replaces the venerable BIOS. The GUID Partition Table assigns a globally unique identifier (GUID) to each partition on your drive. A GUID is a 128-bit value that uniquely identifies your hardware.
GPT drives share some of the constraints associated with MBR discs. GPT drives have the potential to be significantly more significant than their MBR equivalents (with the right settings, a theoretical 256TB drive would work). Without the use of an extra partition, GPT discs can have up to 128 distinct partitions on a Windows system. Other systems provide us with much greater flexibility.
Another key distinction is how GPT drives store boot data. In comparison to the MBR drive, the GPT drive keeps numerous copies of the boot data over many partitions, which simplifies recovery.

Compatibility

Not all versions of Windows can boot from a GPT partitioned drive, with many requiring a UEFI-based system.

  • 64-bit Windows 10, 8/8.1, 7, and Vista all need a UEFI-based system to boot from a GPT drive.
  • 32-bit Windows 10 and 8/8.1 need a UEFI-based system to boot from a GPT drive.
  • 32-bit Windows 7 and Vista cannot boot from a GPT drive.
  • All mentioned Windows versions could read from and write to a GPT drive.

Other operating systems also use GPT systems. For instance, Apple now uses GPT rather than its Apple Partition Table (APT). Furthermore, Linux has built-in support for GPT drives.

How to Convert MBR to GPT

As previously said, GPT is the more current partition table format, providing improved recovery and overall versatility. For a long time, changing an MBR drive to a GPT drive required erasing the drive. However, there are now two solutions available that will convert your drive safely and without data loss. In comparison to the MBR drive, the GPT drive keeps numerous copies of the boot data over many partitions, which simplifies recovery.

Note: There is no going back unless you wipe your drive.

MBR to GPT is a one-way transformation. Please also remember there is a small chance your drive will cease to function after the conversion. While this is a minimal chance, Digital Gyan accepts no responsibility for your hardware if you continue with this tutorial after this warning. In this, the validation step in the upcoming tutorial is crucial.

There is one final check to make before converting your disk. Does your hardware support have UEFI-support? If not, your hardware won’t register the drive following conversion and, if converting a bootable drive, you will not have access to your operating system.

MBR2GPT

Microsoft’s MBR2GPT tool is already on your system as part of the Windows 10 Creators Update.

The tool primarily caters to sysadmins who have to deploy Windows 10 installations on a large number of computers. However, you can use it to switch your MBR drive to GPT with minimal hassle. Here’s how.

  1. First, check your disk number. Complete a Start menu search for Computer Management and select the best match. Select Disk Management and locate the disk you want to convert, noting the disk number. Right-click the disk number, choose Properties and open the Volume Check the current partition type is MBR.
  2. Press Windows + X, then select Command Prompt (Admin) from the menu. If Command Prompt (Admin) is no longer an option, complete a Start menu search for Command Prompt, then right-click and select Run as Administrator.
  3. Now, validate the disk you want to convert. Type mbr2gpt /validate /disk:[enter your disk number here] /allowFullOS
    The validation should only take a moment. If the disk doesn’t meet the conversion requirements, you’ll receive an error. (For instance, the error below came from an invalid USB flash drive as it does not meet the requirements.)
  4. Type mbr2gpt /convert /disk:[enter your disk number here] /allowFullOS and press Enter to begin the conversion. The conversion is rapid, only taking a few seconds.
  5. You need to change your firmware to boot to UEFI mode. After your system restart, press your BIOS/UEFI entry key. Change the boot type to UEFI mode, as opposed to Legacy Mode or other equivalents.

EaseUS Partition Software

The second option for converting MBR to GPT is to use EaseUS Partition Master Professional. Honestly, this is the easier of the two conversion options, using a similar UI to the Windows Disk Management screen. However, EaseUS Partition Software has several additional options, not least of which is the Convert MBR to GPT tool.

On the other hand, EaseUS Partition Master Professional will set you back $39.95, while the Windows integrated MBR2GPT tool is already part of your operating system.

  1. Head to the EaseUS Partition Master site. Purchase the software, download, and install. (Tip: If you’re only converting one drive, grab the Trial version.)
  2. Open EaseUS Partition Master and wait for your drives to load. Locate the drive you want to convert. Select the disk, right-click, and select Convert MBR to GPT.
  3. Press the Apply button on the toolbar. Once you hit apply, your system will reboot. You’ll arrive at an EaseUS Partition Master operation screen that shows the conversion process taking place.
    How to Convert MBR to GPT Without Losing Data in Windows EaseUS Partition Master MBR to GPT conversion
  4. You need to change your firmware to boot to UEFI mode. After your system restart, press your BIOS/UEFI entry key. Change the boot type to UEFI mode, as opposed to Legacy Mode or other equivalents.

In my opinion, EaseUS Partition Master makes the process more comfortable but is slightly slower than its free Microsoft counterpart.

MBR to GPT Conversion Complete!

You’ve successfully changed your old MBR drive to a GPT disc, giving you more control over how you utilise it. If your system fails to boot after conversion, check sure the UEFI boot option is enabled in the BIOS/UEFI settings.

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