MSR and EFI Partitions Are Only Supported on GPT Disks

July 31, 2019

Don't know how to deal with MSR and EFI are only supported on the GPT disk? Look through this article, you will get the best solution of this problem.

The Symptom

When trying to create a new partition with Diskpart on the hard disk, you are likely to receive a message that says MSR and EFI partitions are only supported on GPT disks. This often happens when using Windows recovery options or trying to upgrade to Windows 10.

Error

The Background

While initializing a hard drive, Windows will ask you to make it as GPT or MBR partition style. If your operating system (OS) is installed on a GPT disk, the first partition on that disk must be the Extensible Firmware Interface (EFI) system partition formatted with FAT32, and the Microsoft Reserved partition (MSR) comes behind. To boot the system from a GPT disk, the Unified Extensible Firmware Interface (UEFI) boot mode, largely used by recent hardware must be enabled. Most computers have support for both UEFI and Legacy boot mode, which is for MBR disks. If you only use the GPT disk for data storage, there will be no EFI partition but the MSR partition in the first place of your disk. On MBR disks, it doesn’t require the EFI or MSR partition but the system reserved partition. Therefore, when you try to create an EFI or MSR partition on an MBR disk, WIndows will tell you to convert the selected disk to GPT.

Solution 1: Convert MBR to GPT without data loss

After upgrading to Windows 10 or failed in the attempt, your disk may be miraculously converted to MBR disk, which many users has reported. In this case, if you then want to create EFI partition or MSR partition with Diskpart for wahtever reasons, you definitely will be prompted to convert to GPT disk. To work this around, you need to firstly check whether the UEFI boot mode (for GPT disks) is enabled, then convert the disk to GPT disk. Disk Management can only convert empty disks without any partitions or volumes to GPT, which makes impossible to fix this without data loss. Fortuantely, you can use free third party software AOMEI Partition Assistant Professional to convert system disk to GPT without losing data.

Step 1. Download, install and launch AOMEI Partition Assistant Pro.

Main Interface

Step2. Right click on the disk needs converting, and then select Convert to GPT.

Convert to GPT

Step 3. Click Apply to execute this operation.

Apply

If your cannot boot your system, you can use this program in another computer to create a bootable media, and then use the bootable disk to make the conversion. In addition, if you're a service provider, you can use AOMEI Partition Assistant Technician to solve disk partition problem for your clients.

Solution 2: run fix MBR command

You want to use Windows installation disc to refresh or restore, but it says the disk is locked. Then you use Diskpart to create a new partition, but it told you to convert disk to GPT disk as mentioned above. Your disk is likely an MBR disk, the system misunderstand what partition you want to create. Therefore, it prompts the message. To fix this, you can open an elevated command prompt and run the follwoing commands:

  • Bootrec /fixMBR

  • bootrec /fixBoot

  • bootrec /rebuildBCD

Fix MBR

After that, you should be able to use Diskpart to create partitions without getting the message saying MSR and EFI partitions are only supported on GPT disks. Just bear in mind that there can only be 4 primary partitions at most or 3 primary partitions and lot of logical partitions on an MBR disk.

The Symptom


When trying to create a new partition with Diskpart on the hard disk, you are likely to receive a message that says MSR and EFI partitions are only supported on GPT disks. This often happens when using Windows recovery options or trying to upgrade to Windows 10.

Error

The Background

While initializing a hard drive, Windows will ask you to make it as GPT or MBR partition style. If your operating system (OS) is installed on a GPT disk, the first partition on that disk must be the Extensible Firmware Interface (EFI) system partition formatted with FAT32, and the Microsoft Reserved partition (MSR) comes behind. To boot the system from a GPT disk, the Unified Extensible Firmware Interface (UEFI) boot mode, largely used by recent hardware must be enabled. Most computers have support for both UEFI and Legacy boot mode, which is for MBR disks. If you only use the GPT disk for data storage, there will be no EFI partition but the MSR partition in the first place of your disk. On MBR disks, it doesn’t require the EFI or MSR partition but the system reserved partition. Therefore, when you try to create an EFI or MSR partition on an MBR disk, WIndows will tell you to convert the selected disk to GPT.

Solution 1: Convert MBR to GPT without data loss

After upgrading to Windows 10 or failed in the attempt, your disk may be miraculously converted to MBR disk, which many users has reported. In this case, if you then want to create EFI partition or MSR partition with Diskpart for wahtever reasons, you definitely will be prompted to convert to GPT disk. To work this around, you need to firstly check whether the UEFI boot mode (for GPT disks) is enabled, then convert the disk to GPT disk. Disk Management can only convert empty disks without any partitions or volumes to GPT, which makes impossible to fix this without data loss. Fortuantely, you can use free third party software AOMEI Partition Assistant Professional to convert system disk to GPT without losing data.

Step 1. Download, install and launch AOMEI Partition Assistant Pro.

Main Interface

Step2. Right click on the disk needs converting, and then select Convert to GPT.

Convert to GPT

Step 3. Click Apply to execute this operation.

Apply

If your cannot boot your system, you can use this program in another computer to create a bootable media, and then use the bootable disk to make the conversion. In addition, if you're a service provider, you can use AOMEI Partition Assistant Technician to solve disk partition problem for your clients.

Solution 2: run fix MBR command

You want to use Windows installation disc to refresh or restore, but it says the disk is locked. Then you use Diskpart to create a new partition, but it told you to convert disk to GPT disk as mentioned above. Your disk is likely an MBR disk, the system misunderstand what partition you want to create. Therefore, it prompts the message. To fix this, you can open an elevated command prompt and run the follwoing commands:

  • Bootrec /fixMBR

  • bootrec /fixBoot

  • bootrec /rebuildBCD

Fix MBR

After that, you should be able to use Diskpart to create partitions without getting the message saying MSR and EFI partitions are only supported on GPT disks. Just bear in mind that there can only be 4 primary partitions at most or 3 primary partitions and lot of logical partitions on an MBR disk.