By AOMEI / Last Updated November 29, 2019

Error: the specified disk is not convertible

"Hi all, I need to convert my system disk from MBR to GPT. So, I started by wiping the hard drive. I know that it is impossible to clean the system drive with Windows running, so I then booted the computer from my Windows install disk to try and convert the system hard drive. When I tried to convert the disk to GPT using DiskPart.exe I received the error “The specified disk is not convertible”. Can anyone who can tell me why it happens and what I can do?"

Don’t worry, loads of people have encountered the same problem while converting their system disk to GPT/MBR. We will tell you the some of the possible reasons and solutions for this error.

Possible reasons

When Windows 10, 8, and 7 are installed on an MBR hard drive, the system will be using the Legacy BIOS-based boot mode, whereas a GPT disk will only be able to boot using UEFI mode. When you want to convert a system disk to GPT using Windows, then you will need to wipe the old Windows system. create a GPT partition table, and then reinstall Windows.

Change UEFI/BIOS

To do this using the installation disk, you first need to boot the disc in UEFI mode if you need to convert to GPT using the diskpart.exe commands. Similarly, you will need to change the boot mode to Legacy mode before you boot the disc if you want to convert GPT to MBR.

Convert GPT Diskpart

If you still get the error “the specified disk is not convertible” when using a Windows installation USB or disc, then you will need use professional partition software to convert the system disk to MBR/GPT. If you use professional partition software you won’t need to wipe all of your data from the drive before converting.

Convert system disk to GPT/MBR without affecting OS

If you don’t want to wipe the hard drive, convert the disk, and then manually reinstall Windows, you can choose to directly convert your system disk to GPT or MBR by using AOMEI Partition Assistant Professional. This specialist partition software understands that these two partition styles require different boot modes to load the operating system, and will take care of it for you.

You can refer to the steps below to convert a hard drive with Windows installed on it either to the GPT or MBR format without losing data.

Step 1. Install and run AOMEI Partition Assistant Pro.

Step2. Right click on the disk that it shows “virtual disk service error the specified disk is not convertible” error message, and then select the option “Convert to GPT Disk”.

Convert System Disk to GPT

Step 3. Click “Apply” to begin the conversion.

Apply to GPT System Disk

When the conversion has completed, you need to boot into the BIOS to enable UEFI boot mode before you can load Windows. In addition to using Partition Assistant to convert between MBR to GPT, you can also convert a GPT disk (with an OS installed) to MBR. AOMEI Partition Assistant is even smart enough to handle a GPT disk that has more than 4 partitions, so you won’t have to delete your partitions in advance.

If you have already cleaned your hard drive, then you can create a bootable media device in AOMEI Partition Assistant to boot the computer and convert the disk. In conclusion, AOMEI Partition Assistant can help you solve a variety of conversion issues that you might encounter including the “specified disk is not convertible” error.

* If you are a Windows Server user, then AOMEI Partition Assistant Server Edition will provide you with the perfect solution for any errors that you may encounter!