Convert Disk between MBR and GPT in Windows 10 without Data Loss

MBR and GPT are different disk styles. MBR is short for Main Boot Record, whose maximum size of disk is 2TB. And only allows you to create 4 primary partitions or 3 primary partitions plus 1 extended partition. If you want to build many partitions on MBR disk, the number of primary partition should be no more than three and plus one extended partitions, then you can make logical partitions on extended partition. GPT which is short for DUID Partition Table has no the limitation for the number of partition and the size of disk. But as for GPT, you should know that system installed on GPT disk can only be booted from UEFI (United Extensive Firmware Interface).

Why Convert between MBR and GPT in Windows 10?

It is clear from what I mentioned above; MBR can only support 2TB disk. What does this really mean? For instance, if you have a MBR disk whose size is 3TB, the rest of 1TB will be showed as unallocated space in your windows 10, but you can’t use it. Therefore, in order to take full use of storage space, most of users will choose to convert MBR to GPT.

However, some operating systems such as Windows XP 32-bit, Windows 2003 32-bit, Windows 2000, Windows NT4 don’t support GPT disk. In these operating systems, GPT disk will be shown as GPT protective, and you are not allowed to access data in the disk unless you convert GPT to MBR.

Every coin has two sides, just like MBR and GPT. So among the large number of Windows 10 users, they need to convert MBR to GPT or convert GPT to MBR depending on their own requirements.

How to Convert between MBR and GPT in Windows 10?

Usually, there are 2 common ways for the user of Windows 10 to make conversion between MBR and GPT. The following will show you the details.

Disk Management

Disk Management is a built-in tool in Windows 10 which allows you to create/delete/format/extend/shrink partition, convert to GPT or MBR. To use this tool, you should open it by clicking This PC<Manage<Disk Management. And then right click the disk you want to convert (take Disk 0 for example). In the pop-up windows, you can see “Convert to GPT Disk” is greyed out. With this tool, you can only convert to GPT or MBR when there are no partitions on disk. so you must delete all the partitions on Disk 0 and then you can convert MBR to GPT.

Diskpart Command Line

Diskpart is also a built-in tool in Windows 10, it also can help you manage partitions and do conversion between MBR and GPT. as well as Disk Management in Windows 10, Diskpart only enables you to convert GPT to MBR or convert GPT to MBR when there are no partitions on the disk you plan to operate. If you satisfy the precondition, you can do as follows:
Step 1: Click "Start Menu" > input "diskpart" in the search box and press "Enter" > Click "Yes" to open command prompt.
Step 2: Input "list disk" and press "Enter".
Step 3: Input "select disk n" and press "Enter". n is the number of the disk you want to convert. (take "Disk 1" for example)
Step 4: Input "clean" and press "Enter" to delete all partitions or volumes on the selected disk.
Step 5: Input "convert mbr" and press "Enter" to complete the conversion from GPT to MBR format.

The two methods mentioned above are able to convert MBR disk to GPT or GPT disk to MBR. But both of the methods will need you to delete all the partitions on disk at first. So before you do, you should backup all the data you may wipe and then recover them. It seems you are in the risk of data loss. Can you convert between MBR and GPT in Windows 10 without data loss?

AOMEI Partition Assistant Convert MBR/GPT in Windows 10 without Data Loss

AOMEI Partition Assistant Professional is a powerful software for partition management. It allows users to convert MBR to GPT or convert GPT to MBR without deleting partitions and losing data. Besides this feature, it enables you to make bootable CD, allocated free space, migrate OS to SSD, and more useful features.

Before you do:

• If you want to convert system disk between MBR and GPT styles, please change boot mode between UEFI and Legacy. After conversion GPT disk can only be booted by UEFI.
• If there are more than 4 partitions on GPT disk, you cannot convert GPT to MBR disk unless you delete some unused partitions and limit the primary partition number within four due to the limitation of MBR disk.

Convert GPT to MBR

Step1: Download this software, install and launch it. Right click the disk you want to convert(disk 2) and then choose Convert to MBR Disk.

Step2: Click OK to continue.

Step3: Click Apply to perform all the operations.

Convert MBR to GPT

Download, install and launch the software. Choose the disk you are going to convert and choose Convert to GPT Disk. And then do as the prompt like the steps of converting GPT to MBR.

Note:

For system boot disk conversion between MBR and GPT styles, to guarantee system bootable, you need to enter BIOS and change the boot mode after the conversion is completed.

convert the GPT disk to MBR

1) Log on as administrator account.
2) Click Start button and right-click Computer from the menu.
3) Click Manage.
4) On the Computer Management snap-in, click to select Disk Management from the left pane under Storage category.
5) On the right pane, ensure that the hard disk drive on which you want to install Windows 8 has no partition.
6) Then right-click the name of the disk (e.g. Disk 1) and click Convert to MBR from the context menu. (If the disk already has partition, Convert to MBR option would be grayed out and would be disabled).
7) Try installing Windows 7 now. It should work this time.

If the above fails, when you get to the 'Where do you want to install Windows' screen, assuming you will want 7 installed on the SSD, choose 'Drive Options(Advanced)' and delete all the partitions on the SSD so all you have left is Unallocated Space. Proceed with Install, Windows will do the rest. Then you'll have to do some careful house keeping to make sure all your User data is directed to the HDD, and set up the SDD for max efficiency... personally I would stick with 8 and tailor it to your own tastes...

Hope this helps.

How to Convert GPT Disk to MBR Disk

GUID Partition Table, short for GPT, is a standard for the layout of the partition table on a physical hard disk. Although it forms a part of the Extensible Firmware Interface (EFI) standard, it is also used on some BIOS systems because of the limitations of MBR partition tables, which restrict maximum disk size to 2 TB.

Master Boot Record is short for MBR. It is the 512-byte boot sector that is the first sector of a partitioned data storage device such as a hard disk. When a data storage device has been partitioned with the MBR partition table scheme, the master boot record contains the primary partition entries in its partition table

The following will show you how to convert a GPT disk to a MBR disk with EaseUS Partition Master, Windows Disk Management and command prompt for free.

Solution 1: Convert GPT disk to MBR disk with EaseUS Partition Master

EaseUS Partition Master can directly convert GPT disk to MBR disk without any data loss (hard disk with system installed is not supported). You can also use EaseUS free partition software to solve other partitions cases such as tomove gpt partition, partition gpt disk etc. Compared to Disk management and command prompt, it won't require to deleted disk volumes. Therefore, it is the safest and the most reliable way.

1. Launch EaseUS Partition Master.

2. Select the GPT disk that you want to convert to MBR disk. And then click "Convert GPT to MBR".

3. Choose “Apply”, you will see that the GPT disk has been converted to MBR disk. All data is safe with EaseUS partition manager software.

Tips to convert gpt to mbr with Disk Management and Command Prompt:

1. You must have administrator privilege to do this in Windows.

2. Before you convert a disk, be sure to backup anything on the GPT disk that you want to convert to MBR disk. Converting the disk requires that all partitions and volumes are deleted on the disk first.

Solution 2: Convert GPT disk to MBR disk with Windows Disk Management

1. Right click "My Computer" and choose "Manage" -> "Storage" -> "Disk Management".

2. Delete all volumes on the GPT hard disk which you want to convert to MBR disk. This action would cause data loss if there are important data in your disk volume.

3. Right click on the hard disk 1 and choose "Convert to MBR Disk". After you convert GPT disk to MBR disk, you can create partitions on the now MBR disk if you like.

Solution 3: Convert GPT disk to MBR disk via diskpart command

In the following case, I would like to convert disk 1 into MBR disk.

1. Input “DiskPart” at the search bar.

2. Type list disk and press enter.

3. Type select disk 1 and press enter.

4. Type detail disk and press enter. This will give you a list of all the volumes on the selected disk. If you do not have any volumes listed, then you can go to step 7.

5. Type select volume 5 and press enter.

6. Type delete volume and press enter.

Repeat steps 5 and 6 for each volume listed in step 4 until you have deleted all the volumes.

7. Type select disk 1 and press enter.

8. Type convert mbr and press enter.

9. Type exit and press enter.

Now you’ve successfully converted gpt to mbr. If you do not waste time backuping up data, EaseUS Partition Master can be your best choice. You can also read the tutorial of converting MBR disk to GPT disk.

How To install Windows 7 on a pre-installed Windows 8 computer

Boot

Many new Windows8 pre-installed systems will not boot from CdRom. To enable booting from CdRom you need to get into the Bios of your computer.

In this case (Acer laptop), press and hold the F2 key while restarting the system. Restarting is important; Shutdown/startup will not work with the F2 key.

• Once in the Bios, go to the Boot section and set the CdROm device as primary boot device.
• Disable UEFI boot
• Exit with save & reboot
• Startup the computer using a 3rd party boot manager that supports GPT/MBR boot record management. In this case we used an Acronis Boot Disk (created with Acronis True Image 2013).

Install - step 1 (Acronis)

Windows 7 will only install on a disk/partition with a MBR (Master Boot Record) partition table

• From the Acronis boot menu, select True Image
• Choose Tools & Utilities from the left menu and Add New Disk -> Next
• Select your hard disk from the list -> Next
• Ok to confirm deletion of all data and start paritioning --> ### double check that you have the correct disk, to prevent data loss !! ###
• Select the required disk initialization method: MBR -> Next
• Create partition(s) -> Next
• Specify settings for the partition being created -> Accept
• Proceed. MBR partition table will be created on the new disk.
• Finish. Exit True image, remove the Acronis boot CD and restart your computer, using a Windows7 boot CD

Install - step 2 (Windows)

Install Windows7 on the newly created MBR disk.

For my Dell Inspirion 15R SE I had to go to the UEFI with F2 set secure boot to off and chnage the option Load Legacy Option ROM to true.

After a reboot you can boot from Windows 7 DVD (press F12 to see the boot menu and select the DVD) and install Windows 7.