In this post, we tell how to convert disk from MBR to GPT in Server 2016 via MBR2GPT.exe. Besides, a more powerful converter will also be shared for converting disk between MBR and GPT partition styles without data loss.
MBR2GPT.exe is a professional tool provided by Microsoft and runs from the command prompt. It is able to convert a boot disk from the Master Boot Record (MBR) to the GUID Partition Table (GPT) partition style without modifying or deleting anything on the selected disk.
On Windows Server 2019 and Windows 10 (1703 and later versions), you can convert MBR to GPT with the mbr2gpt command within Windows. But to use mbr2gpt.exe on Windows Server 2016, you need to create bootable media with Windows Preinstallation Environment (Windows PE). Meanwhile, you should remember this tool can only convert MBR-formatted system disk to the GPT partition format. Namely, you cannot use it to either convert GPT system disk to MBR or convert any non-system disks to MBR/GPT.
In this part, we will introduce how to convert MBR to GPT in Windows Server 2016 without data loss via the MBR2GPT.exe tool. Before that, please check out the following disk partition prerequisites:
1. This disk is using MBR partition style and contains 3 primary partitions at most; 2. One of the partitions on the MBR system disk is set as active and is the system partition; 3. The MBR disk does not contain any extended or logical partitions inside; 4. All partitions on this MBR disk are recognized by Windows. Any existing Ext2, Ext3, or Ext4 partitions will make MBR2GPT.exe fail.
If your disk partition configuration doesn't satisfy those requirements, the MBR2GPT command will report the error - "Validating layout, disk sector size is: 512 bytes Disk layout validating failed for disk 0", "MBR2GPT: Conversion failed". If your disk partition configuration meets the requirements, you also have to ensure that your motherboard supports UEFI boot mode, because you need to change the boot mode from BIOS Legacy to UEFI for successful startup after conversion. Then, follow the steps to use MBR2GPT.exe to convert the MBR disk to GPT in Server 2016 without losing data.
Attention: an EFI system partition (ESP) will be created in the process. MBR2GPT will shrink the System Reserved partition first. If there is not enough free space in it, MBR2GPT will shrink the OS drive. Then, the EFI partition will be created behind the C drive. As a result, C drive cannot be extended forever by Windows native tools. To avoid this serious issue, you can extend System Reserved partition in advance.
Step 1. Create a bootable Windows Server 2016 disc or USB drive with the corresponding ISO files.
Step 2. Boot from the bootable media, click Next in the Windows Setup window and then click Repair your computer.
Step 3. Click Troubleshoot in the next window, then click Command Prompt.
Step 4. Then input the following two commands in turn and press Enter after each one.
● cd.. ● mbr2gpt /convert
To use MBR2GPT.exe to change system disk from MBR to GPT in Windows Server 2012 or 2016, the steps are similar.
From above, we know that using MBR2GPT.exe Server 2016 to convert the system disk from MBR to GPT requires the Server bootable media and needs to proceed in the WinPE mode. All make the whole conversion complicated and time-consuming. So, here we would like to share a much more powerful MBR to GPT converter named AOMEI Partition Assistant Server.
Compared with MBR2GPT.exe, this disk partition manager can do: 1. convert system disk from MBR to GPT, or GPT to MBR partition styles in Server 2022/2019/2016/2012/2008/2003 and Windows 11/10/8/7/XP/Vista; 2. convert non-system disk between MBR and GPT; 3. perform such conversion within Windows as long as it can boot up as normal.
To convert Server system disk to GPT, refer to the steps (you can try the demo version first):
Step 1. Install and launch AOMEI Partition Assistant Server. Right-click the system disk and choose “Convert to GPT”.
Step 2. In the pop-out mini window, click “OK” to confirm the operation.
Step 3. Click “Apply” to commit the pending operation.
Tip: If you cannot boot into Windows Server operating system, you can also use this tool to create a bootable USB stick, and then convert disk between MBR and GPT without loading OS.
In this article, we have shown how to convert the system disk to GPT via MBR2GPT.exe Server 2016. If you are not familiar with creating bootable media and how to boot into the Windows PE environment, you can switch to AOMEI Partition Assistant Server. This versatile tool can make MBR and GPT conversion more convenient and straightforward.
Moreover, AOMEI Partition Assistant Server can also move Server OS to new hard drive (SSD/HDD), convert primary partition to logical drive, and vice versa without losing data, recover deleted partitions, and more. To install such amazing software on unlimited PC or Server, you can go for the Unlimited Version. The Unlimited edition has a helpful function, Create Portable Version, enabling you to create AOMEI Partition Assistant to a removable device and use it on computers without installation.