How to Convert MBR to GPT Using Paragon Hard Disk Manager 15 Professional


This document explains how to use Paragon Hard Disk Manager 15 Professional to convert an existing disk from MBR to GPT and set the allocation cluster size to 64K from the Microsoft default. This can be done on a disk with data without data loss.


First install Paragon Hard Disk Manager 15 on your system. This is a paid program and requires keys to install. Installation is simple and does not require a reboot. Now that we are installed start up the program so we can start the process.

Now that the installation has completed, open the application. Select disk to change

Hard Disk Manager

Right click and select Convert to GPT hard disk

Hard Disk Manager

Hard Disk Manager

Click Yes.

You will see a popup do not click at this time.

Hard Disk Manager

Right click on disk and select change cluster size.

Hard Disk Manager

We are wanting 64K clusters, select the drop down and click 128 and click Yes.

Hard Disk Manager

If we look to the right we see what we are wanting.

Hard Disk Manager

Now we are ready. Click the check mark to start operations.

Hard Disk Manager

Click Yes.

Hard Disk Manager

The operations will start and there will be a status. It is possible the system may reboot.

Hard Disk Manager

You will see this message. Click Restart the computer.

Hard Disk Manager


Now we wait. This process can take sometime. For example a 2 TB system with 1 TB consumed took 5 hours to convert to GPT with 128K (64K) allocation.

Once the conversion has completed the server will reboot and we can verify the settings using diskpart.

DISKPART> list volume

Volume ### Ltr Label Fs Type Size Status Info
———- — ———– —– ———- ——- ——— ——–
Volume 0 Z DVD-ROM 0 B No Media
Volume 1 C GA_OS NTFS Partition 81 GB Healthy System
Volume 2 E GA_Apps NTFS Partition 59 GB Healthy
Volume 3 F GA_Data NTFS Partition 1949 GB Healthy
Volume 4 G GA_Backup NTFS Partition 1535 GB Healthy
Volume 5 H GA_Logs NTFS Partition 799 GB Healthy
Volume 6 I GA_Temp NTFS Partition 249 GB Healthy
Volume 7 J GA_Install_ NTFS Partition 149 GB Healthy

DISKPART> select volume 3

Volume 3 is the selected volume.

DISKPART> filesystem

Current File System

Type : NTFS
Allocation Unit Size : 64K
Flags : 00000000

File Systems Supported for Formatting

Type : NTFS (Default)
Allocation Unit Sizes: 512, 1024, 2048, 4096, 8192, 16K, 32K, 64K (Default)

Type : REFS
Allocation Unit Sizes: 64K (Default)



As you can see we can Convert MBR to GPT Using Paragon Hard Disk Manager 15 without data loss.



3 Responses to “How to Convert MBR to GPT Using Paragon Hard Disk Manager 15 Professional”

  1. Cesar says:

    Is this possible to transfer a MBR Windows installation (x64)
    into another bigger GPT (3TB) drive?
    I tried moving it and then converting. But Windows no longer detects it in UEFI mode.

  2. Kenneth says:

    Is it possible to convert mbr to gpt without data loss in your community edition

    I get a warning about the windows OS what in particular is the warning addressing ? can I go ahead with the operation

  3. isidroco says:

    Paragon won’t keep device bootable after convertion.
    AOMEI Partition Assistant v7.5.1.0 (or later) will convert to GPT and take care of UEFI boot of the installed OS.
    Solution to non bootable OS after convertion is to boot with an windows installer USB. Go to Command Prompt (Shift-F10) and perform:
    lis dis
    sele dis 0
    (use dis N where your windows is)
    lis par
    sele par 1
    (use par N where your windows is)
    lis vol
    sele vol 1
    (use vol N where your windows is)
    ass letter W
    shrink desired=640
    cre par pri
    for quick fs=fat32 label Sys
    ass letter S

    bcdboot W:\windows /s S: /f UEFI

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