Solved: MSR and EFI are Only Supported on the GPT Disk

• Error: MSR and EFI partitions are only supported on the GPT disk
• Overview of MSR and EFI partitions on GPT disk
• Solutions to “MSR and EFI are only supported on the GPT disk” error
• Summary

Error: MSR and EFI partitions are only supported on the GPT disk

“Hi every one! I need help on Diskpart. I am using Windows 8, when I boot with the Win 8 installation DVD to refresh or restore. It cannot be finished and says disk is locked and only command prompt working. I was advised to use diskpart and i did that. I successfully selected the disk 0 and listed all partitions. But when i was trying to create partition, the message pops out saying this: MSR and EFI partitions are only supported on GPT disks. Convert the selected disk to GPT and try again.”

When trying to create a new partition with Diskpart on the hard disk, most users will be 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 and upgrade to Windows 11, because upgrading from Windows 10 to Windows 11 requires the UEFI boot.

Overview of MSR and EFI partitions on GPT disk

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 the FAT32 file system, and the Microsoft Reserved partition (MSR) comes behind.

The EFI partition is used by computers adhering to the UEFI (Unified Extensible Firmware Interface). When it is booted, the UEFI firmware loads files stored on the ESI partition to start installed OS and various utilities. The MSR (Microsoft Reserved Partition) is created to reserve a partition of disk space for possible subsequent use by a Windows OS on a separate partition. There is no meaningful data in the MSR partition.

To boot OS from a GPT disk, the Unified Extensible Firmware Interface (UEFI) boot mode must be enabled. Most computers support 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 this disk. On MBR disks, it doesn’t require the EFI or MSR partition but the system reserved partition. So when you try to create an EFI or MSR partition on an MBR disk, Windows will tell you that MSR and EFI partitions are only supported on GPT disks.

Solutions to “MSR and EFI are only supported on the GPT disk” error

For the above error message, you can convert the disk to GPT as it prompts, or try other different commands to fix MBR. Next comes the details.

1. Convert to GPT disk without data loss and create MSR /EFI partitions

From the error message, we can easily know that the direct solution is to convert the selected disk from MBR to GPT. To do this, you can use the cmd.exe or Disk Management, but they can only convert an empty disk to MBR or GPT. In other words, you have to delete all partitions along with all data on the disk before conversion. That means you will lose everything and reinstall OS from scratch afterward.

So, is there a way to convert the selected disk to GPT without deleting any partitions? Fortunately, you can use the third-party software AOMEI Partition Assistant Professional to convert both system and data disk to GPT/MBR without removing partitions or losing data. You can download the demo version and refer to the following steps.

Note: you need to firstly check whether the UEFI boot mode (for GPT disks) is enabled.

Step 1. Install and launch AOMEI Partition Assistant Pro.Right-click on the disk needs converting, and then select “Convert to GPT”.

Step 2. Click on “OK” to confirm your operation if everything is correct.

Step 3. Click "Apply" to execute this operation.

If you cannot boot your system, you can use this program in another computer to create a bootable media, and load the AOMEI Partition Assistant Professional from the media on the computer where you cannot create EFI and MSR partitions, then convert the disk to GPT without loading operating system. 

2. Run fix MBR command

If your computer does not supports EFI or UEFI boot mode and cannot boot from GPT disk, converting the MBR disk to GPT is not advised. In this case, you can open an elevated command prompt and run the follwoing commands:

▸bootrec /fixMBR

▸bootrec /fixBoot

▸bootrec /rebuildBCD

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.

Summary

So, when the error message “MSR and EFI partitions are only supported on GPT disks. Convert the selected disk to GPT and try again”, you can try the above 2 solutions. The AOMEI Partition Assistant software can also help delete EFI partition, clone EFI partitiont to another drive, and more. If you are running Windows Server operating system, please switch to AOMEI Partition Assistant Server.