By AOMEI / Last Updated September 11, 2019

Error: the specified disk is not convertible

"Hello, I need to convert my system disk from MBR to GPT. Thus, I wiped the hard drive clean. I know that it is impossible to clean the system drive with Windows running, so I boot my computer from a Windows installation disk to convert system hard drive. However, I received an error “The specified disk is not convertible” when I try to convert disk to GPT with DiskPart.exe. Is there anyone who can tell me why it happens and how solve it?"

Actually, there are lot of people have meet the same problem while converting a system disk to GPT/MBR. Fortunately, here we got the possible reason and solutions for this error.

Possible reason

When Windows 10/8/7 installed on an MBR hard drive, the system is using Legacy BIOS-based boot mode. GPT disk can only boot on UEFI mode. When you want to convert the system disk to GPT, Windows needs to wipe the old Windows system and create GPT partition table.


Therefore, you need to boot the installation disc from UEFI mode to use convert GPT command in diskpart.exe. Similarly, you need to change the boot mode to Legacy mode before you boot the installation disc to convert GPT to MBR.

Convert GPT Diskpart

If you still get the error “the specified disk is not convertible” using USB Windows installation drive or disc, you can use professional partition software to convert disk to MBR/GPT without data loss.

Convert system disk to GPT/MBR without affecting OS

Rather than wipe the hard drive, convert the disk, and then reinstall Windows, you can directly convert a system disk to GPT or MBR with AOMEI Partition Assistant Professional . This software understands that those two types of partition style requires different boot partitions to boot, so it will take care of it.

You can refer to the steps below to convert a hard drive with Windows installed to GPT or MBR partition style without data loss.

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, and then select the option “Convert to GPT Disk”.

Convert System Disk to GPT

Step 3. Click “Apply” to apply this operation.

Apply to GPT System Disk

When the process complete, you need to boot into BIOS to enable UEFI boot before you can enter Windows. Similarly, you can also convert GPT disk to MBR along with system installed. The software is smart enough to handle when the GPT disk has more than 4 partitions.

If you have successfully clean your hard drive, you can create a bootable media to boot the computer and convert the disk. In conclusion, AOMEI Partition Assistant can help you solve the problem that the specified disk is not convertible.

* If you are Windows Server users, the AOMEI Partition Assistant Server Edition is suitable for you.