By Michael / Last Updated September 26, 2021


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' "


Before getting this error message, you probably have restore 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, you will also give you such error when you try to access it.


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.

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.

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

This process will be complete in AOMEI Pre-OS mode, so your computer will reboot. Until it finishes, 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.