Found Invalid GPT and Valid MBR in Windows – Quick Fix

Get the return message “Found invalid GPT and valid MBR; converting MBR to GPT format in memory” when you use GDisk to convert MBR to GPT in Windows? Learn why the error occur and how to solve it in a simple way.


By Lucas / Updated on May 12, 2023

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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 got 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 trouble? Keep reading.

Possible reasons for '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:

1. 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.

CMD run as administrator

2. Your computer motherboard or operating system does not support UEFI boot. This is a cause explained after the error message. Most previous versions of Windows cannot boot from a GPT disk except on a UEFI-based computer, and most varieties before Vista cannot read GPT disks. Therefore, confirm these qualifications before you start. (Click the Start button and go to All Apps> Windows Administrative Tools > System Information> BIOS Mode)

System info Legacy

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

Fix by converting MBR to GPT without data loss

If you cannot fix the “invalid GPT and valid MBR” error after all trying, it is a wise option to turn to MBR to GPT converting software. AOMEI Partition Assistant Professional is a user-friendly software that allows you to convert the hard drive from MBR to GPT without losing data, regardless of system disk or data disk. Windows 11/10/8.1/8/7/XP/Vista supported. Let’s get to know the specific steps now.

Free Download Win 11/10/8.1/8/7/XP
Secure Download

1. Install and run AOMEI Partition Assistant on your computer. Find the disk you want to convert, right-click it, and select "Convert to GPT" from the menu, or click the disk and choose "Convert to GPT" from the right panel.

Convert boot disk to GPT

2. Click "OK" to continue the operation.


3. Click "Apply" and then "Proceed" to commit. After that, shut down your computer after conversion. Change Legacy to UEFI if you have converted the system disk to GPT partition style.


1. To convert MBR to GPT in Windows PE with AOMEI Partition Assistant, you can use the "Make Bootable Media" feature to achieve the task.
2. Please turn to AOMEI Partition Assistant Server Edition if you're a Windows Server user.


Run gdisk with administrative privilege or make sure your Windows version and motherboard support UEFI boot when you face the prompt: Found invalid GPT and valid MBR. Also, an easier way to convert MBR to GPT is provided followed by AOMEI Partition Assistant 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, clone disk/partition, SSD secure erase, and moving programs without reinstalling, etc are also available.

Lucas · Staff Editor
I prefer peaceful and quiet life during vacation,but sometimes I watch football match if my favorite club performs brilliantly in that season. And I love reading, painting and calligraphy, thus I send my friends festival handwriting cards every year.