By Lucas / Last Updated June 22, 2021

The error: Found invalid GPT and valid MBR

“I’d like to convert my hard drive to GPT partition style with GDisk command. After I input gdisk32.exe 0: and press Enter, only to get this return message: Found invalid GPT and valid MBR; converting MBR to GPT format in memory. THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by typing ‘q’ if you don’t want to convert your MBR partitions to GPT format!

Found invalid GPT and valid MBR

It says the operation may destroy my data, so I typed ‘q’ to exit. Why would that happen? And what should I do to get my disk partition style changed from MBR to GPT, better without losing data?”

It is an error that may occur when using command lines with GDisk, SGDisk, or Clonezilla. Why would you get this GDisk Found invalid GPT and valid MBR error? Is there any way to get you out of the trouble? Keep reading.

How to fix GDisk Found invalid GPT and valid MBR?

Before learning how to fix the error, you may wonder the reasons account for the error. In general, there are two possible causes to explain your problem.

  • You did not launch with administrative privileges. Under Windows, you need to right-click the Command Prompt program and select the “Run as Administrator” option, and then use the resulting window to run gdisk.

  • Your computer motherboard or operating system does not support UEFI boot. This is a cause that actually explained after the error message. Most versions of Windows cannot boot from a GPT disk except on a UEFI-based computer, and most varieties prior to Vista cannot read GPT disks. Therefore, confirm these qualifications before you start.

Please note that 32-bit system does not support boot from a GPT disk which contains operating system. However, it is supported to convert MBR to GPT on data disk in 32-bit system (Download free MBR to GPT converter).

Better way to convert MBR to GPT without data loss

If you cannot fix “invalid GPT and valid MBR” error after all trying, it is a wise move to turn to other MBR to GPT converting software. AOMEI Partition Assistant Professional is the easiest software that allows you to convert hard drive from/to GPT without losing data, regardless of system disk or data disk. Windows 10/8.1/8/7/XP/Vista supported. Let’s get to know the specific steps now.

1. Install and run AOMEI Partition Assistant on your computer. Find the disk you want to convert and right-click it. Select Convert to GPT Disk from the menu.

Convert to GPT Disk

2. Confirm the operation.

Confirm Conversion

3. Click Apply and then Proceed to commit the operation.

Apply and Proceed

4. (Optional) Shutdown your computer after conversion. Change Legacy to UEFI if you have converted system disk to GPT partition style.


  • To convert MBR to GPT in Windows PE with AOMEI Partition Assistant, you can use "Make Bootable Media" feature to achieve the task.

  • Please turn to AOMEI Partition Assistant Server Edition if you want to, for example, convert MBR to GPT in Server 2012.


Run gdisk with administrative privilege or make sure your Windows version and motherboard support UEFI boot when you facing the prompt: Found invalid GPT and valid MBR. Also, an easier way to convert MBR to GPT is provided followed by as a workaround if you cannot get out of the trouble caused by gdisk or clonezilla.

Except for MBR & GPT converting, you can also perform OS migration to SSD while keeping files on HDD with AOMEI Partition Assistant to gain better performance. Changing partition file system without formatting is also available.