By Michael / Last Updated January 27, 2022

Symptom of the GPT error

When you try to format raw space or to create a new partition out of the unallocated space on your hard drive in Disk Management, you might get the following error message:

"the selected GPT formatted disk contains a partition which is not of type 'PARTITION_BASIC_DATA_GUID' and is both preceded and followed by a partition type 'PARTITION_BASIC_DATA_GUID' "

not of a type error

Why does the format or the partition creation fail?

Before getting this error message, you probably have restored a backup from a smaller GPT disk and the destination disk was using MBR partition table before. The restore process will overwrite data of the large disk with GPT partition table. The problem is that it only convert part of the hard drive to GPT without cleaning the rest space.

Besides system restore, any process trying to install system with GPT partition table by overwriting the destination disk may also fail to convert the entire hard drive to GPT partition style. Therefore, you will receive this error message. If you have created GPT protective partition format on this hard drive, it will also give you such error when you try to access it.

Best solution to convert GPT to MBR without data loss

To fix this problem, you can simply convert the disk to MBR if you are sure you want an MBR disk as your boot disk. If you're planning a Windows 11 upgrade later, we suggest you don't convert it, because Windows 11 can only boot in UEFI mode that’s supported only by GPT.

To convert GPT to MBR disk with Disk Management or DiskPart utility will require deleting all partitions on the hard drive. Fortunately, AOMEI Partition Assistant Professional is able to convert GPT to MBR without losing data or affecting OS, and it works the same to convert MBR to GPT. After the conversion, you shall be able to get rid of the GPT protective partition in windows 11/10/8/7 to convert GPT to MBR without data loss. What’s more, besides the GPT MBR conversion feature, the AOMEI product also allows you to convert between primary drive and logical drive and between NTFS and FAT32 partition.

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Step1: Download and run AOMEI Partition Assistant on your computer. In its main interface, you can see all status of your hard drives and partitions on the computer.

Step2: Right-click on the disk that gave you the error and then select “Convert to MBR Disk”.

Convert Data Disk to MBR

Step3: Click “OK” to confirm the process.

OK to MBR Data Disk

Step4: Then you can preview the partition layout after the conversion. It is as you required, click “Apply” t apply the operation.

Apply to MBR Data Disk

Convert GPT to MBR with Disk Management and DiskPart

If you are not satisfied with any third-party software and still insist on the traditional method, here, you'll learn to convert GPT to MBR with Windows built-in Disk Management and DiskPart utilities. 

Use Disk Management

1. Right-click on "This PC" on the desktop and select "Manage".

2. Select "Disk Management" under the "Storage" tab.

3. Select and right-click on the hard disk you want to convert and select "Convert to MBR Disk". If there're partitions on the disk, the option will be greyed out as the screenshot shows.

convert to gpt greyed out

Use DiskPart

1. In the search box, type "DiskPart" and hit "ENTER".

2. Click on "Yes" for confirmation.

3. Type "list disk" to list all hard disks on your PC and hit "ENTER".

4. Type "select disk *" and hit "ENTER". "*" represents the disk you want to convert.

5. Type "clean" to delete all partitions on the hard disk and hit "ENTER".

6. Type "convert mbr" and hit "ENTER" to convert the disk to MBR.

gpt to mbr diskpart

Change UEFI to Legacy after the GPT MBR conversion

1. In the course of Windows startup, continuously press a specific key, usually it’s Del for desktops and F2 for laptops, to enter BIOS.

2. Under the “Boot” tab, change UEFI to BIOS.

3. Hit F10 to save the settings and then, quit BIOS.

uefi to legacy


This process will be complete in AOMEI Pre-OS mode, so your computer will reboot. When it’s completed, Windows will be loaded again. Then you can create a new partition or merge the unallocated space to one of the existing partitions without having the error that the selected GPT formatted disk contains a partition that is not of type. This Professional edition only works on Windows PCs. If you want it to run on a Windows Server, you can try the AOMEI Partition Assistant Server.