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 safely change your partition table without suffering any data loss. And the best part is how supremely easy it is (as well as completely free). Let’s take a look at how you can convert your MBR disk to GPT—without losing a scrap of data.
MBR is the older of the two and therefore is compatible with a wider range of systems. MBR was developed for IBM PCs and, as such, was the primary partition table choice for Windows machines stretching for quite some time. The Master Boot Record takes its name from its location at the beginning of the drive, containing the bootloader for the operating system and information about the drive partitions.
MBR only works with drives up to 2TB in size. Furthermore, an MBR drive can only have four primary partitions. This was fine when a 2TB was a substantial outlay, but you can now pick up an 8TB drive, like a Seagate Barracuda, for an affordable price.
GPT is the newer of the two. GPT is closely associated with UEFI, the firmware solution modernizing the old alternative, BIOS. GUID Partition Table assigns every partition on your drive a globally unique identifier (GUID) which is a 128-bit number that identifies only your hardware (a 128-bit integer has a maximum value of 1.7 x 10^39—a phenomenally large number).
GPT drives suffer few of the limitations of an MBR drive. GPT drives can be vastly larger than their MBR counterparts (with the right settings, a theoretical 256TB drive would work). On a Windows system, GPT drives can have up to 128 different partitions without using an extended partition. Other systems allow even more.
Not all versions of Windows can boot from a GPT partitioned drive, with many requiring a UEFI-based system.
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.
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 an extremely small chance, MakeUseOf and I accept no responsibility for your hardware if you continue with this tutorial after this warning. In this, the validation step in the upcoming tutorial is very important.
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.
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.
In my opinion, EaseUS Partition Master makes the process easier but is slightly slower than its free Microsoft counterpart.