How to convert a GPT disk to MBR
Converting GPT to MBR may be required in different cases. A common option is an error. Installing Windows on this drive is not possible. The selected drive has a GPT partition style, which occurs when you try to install the x86 version of Windows 7 on a disk with a GPT partition system or on a computer without a UEFI BIOS. Although other options are possible when it may be needed.
In order to convert GPT to MBR you can use standard Windows tools (including during installation) or special programs designed for these purposes. In this instruction I will show various conversion methods. Also at the end of the manual there is a video that shows how to convert a disk to MBR, including without data loss. Additionally: methods of reverse conversion from MBR to GPT, including without data loss, are described in the instructions: The table of MBR sections is located on the selected disk.
Convert to MBR when installing Windows via command line
This method is suitable if, as described above, you see a message stating that installing Windows 7 on this drive is not possible due to the GPT partition style. However, the same method can be used not only during the installation of the operating system, but also simply when working in it (for a non-system HDD).
I remind you: all data from the hard drive will be deleted. So, here is what you need to do to change the partition style from GPT to MBR using the command line (below is a picture with all the commands):
When installing Windows (for example, at the stage of selecting partitions, but it can also be done elsewhere), press Shift + F10 on the keyboard and the command line will open. If you do the same in Windows, then the command line must be run as administrator.
Type diskpart and then list disk to display a list of physical disks connected to the computer.
Enter the select disk N command, where N is the number of the disk you want to convert.
Now you can do two ways: enter the clean command to clean the disk completely (all partitions will be deleted), or delete partitions one by one manually using the detail disk, select volume and delete volume commands (this is the method used in the screenshot, but simply enter clean will be faster).
Enter the convert mbr command to convert the disk to MBR.
Use Exit to exit Diskpart, then close the command line and continue installing Windows – now the error will not appear. You can also create partitions by clicking “Configure disk” in the window for selecting a partition for installation.
As you can see, there is nothing complicated in converting the disk. If you have any questions, ask in the comments.
Convert GPT to MBR using Windows Disk Management
The next way to convert the partition style requires a running Windows 7 or 8 (8.1) OS on the computer, and therefore is applicable only to a physical hard drive that is not a system one.
First of all, go to disk management, for this the easiest way is to press the Win + R keys on the computer keyboard and enter diskmgmt.msc
In disk management, find the hard drive that you want to convert and delete all partitions from it: for this, right-click on the partition and select “Delete Volume” in the context menu. Repeat for each volume on the HDD.
And the last: right-click on the disk name and select “Convert to MBR-disk” in the menu.
After the operation is completed, you can recreate the necessary partition structure on the HDD.
Programs for converting between GPT and MBR, including without data loss
In addition to the usual methods implemented in Windows itself, for converting disks from GPT to MBR and vice versa, you can use partition management programs and HDDs. Among such programs are Acronis Disk Director and Minitool Partition Wizard. However, they are paid.
I am also familiar with one free program that can convert a disk to MBR without data loss – Aomei Partition Assistant, but I have not studied it in detail, although everything speaks in favor of the fact that it should work. I’ll try to write a review of this program a little later, I think it will be useful, besides the possibilities are not limited to changing the style of partitions on a disk, you can convert NTFS to FAT32, work with partitions, create bootable flash drives and more. Update: another one is the Minitool Partition Wizard.