By AOMEI / Last Updated August 19, 2019

Quick story

There was one user who decided to use a 3TB hard drive. At that time, his computer used Legacy boot. He knew that he had to convert to GPT disk in order to use the full 3TB capacity. Then he used DiskPart.exe to convert MBR to GPT, but he received an error message:

The operation is not allowed on a disk that contains a pagefile volume.

Diskpart Error

He even disabled page files in Control Panel and deleted the file c:\pagefile.sys in File Explorer to no valid. What did he miss?

The truth is that DiskPart.exe can only convert an empty hard disk, not a partition, to GPT or MBR partition style. Therefore, if you ever need to convert a hard drive to MBR or GPT with DiskPart.exe, you need to use “clean” command to delete all partitions on that disk before using “convert gpt”. However, certainly, you cannotwipe a hard drivecontaining Windows system which is now running.

Do it the right way

As mentioned, this method will get everything on the disk deleted. You’d better create a backup of the hard drive before applying the following steps.

1. Boot your computer into BIOS to enable UEFI boot mode and exit.

2. Boot your computer from a Windows installation CD or USB disk.

3. At the screen to select where to install Windows, press Shift + F10 to open a command prompt window.

Install Windows

4. Type the following:

  • Diskpart

  • List disk

  • Select disk [disknumber]

  • Clean

  • Convert gpt

Diskpart Convert GPT

5. Then this convert MBR to GPT issue is resolved. After seeing the confirmation message, you can close this windows and go back to install Windows on GPT disk.

An easier way (without data loss)

You can also change Legacy mode to UEFI without reinstalling Windows if you use the help of partition software AOMEI Partition Assistant. It allows you to convert a system disk to MBR or GPT without affecting OS. In other words, once the conversion is done, you can change to UEFI or Legacy boot mode and then boot your Windows 10/8/7 without reinstallation.

You can follow the steps below to convert a boot hard drive to GPT without data loss:

Step 1. Get AOMEI Partition Assistant Pro.

Step2. Right click on the disk that not allowed you to convert because of pagefile volume, and then select the option “Convert to GPT”.

Convert System Disk to GPT

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

Apply to GPT System Disk

Situations like “the operation is not allowed on a disk that contains a pagefile volume” will never happen with AOMEI Partition Assistant because the whole process does not interfere pagefile and all the data remain intact.

Besides that, this software can also be used to resize partition, allocate free space, and convert dynamic disk to basic without data loss.