Ways to troubleshoot MBR partition errors when reinstalling Windows

There are 2 types of partitions - MBR and GPT, and many users when trying to install Windows are faced with the error "There is an MBR partition table on the disk". What caused and what are the methods of solution? Before you start converting, you need to understand their differences. The MBR is an earlier partition structure, it was developed back in 1983. MBR contains a specific boot sector, which allows you to load the operating system.

Methods of eliminating errors when installing Windows "On the disk is a table of MBR-partitions."

Why an error occurs

MBR errors can have three different reasons:

  • Virus;
  • Disk failure;
  • Overwrite the MBR caused by the program.

Everyone knows about the effects of a PC infection by a virus. Many of them target the main boot area, as this is the most important part of your hard drive. HDD crashes are also the main cause of the appearance of the “MBR Partitions Table on the selected disk” window. If the hard drive area with the MBR contains several defective clusters, then the boot record will be unreadable. Some programs also occasionally overwrite a part of the MBR, causing damage to it.

How to convert MBR to GPT

This structure parameter has its limitations and is valid only with hard drives smaller than 2 TB. If several years ago it was not a serious problem, with the increase in the number of large HDDs, it is not surprising that the MBR standard is already outdated. Using the MBR structure, you can have up to four primary partitions, which is a problem for some users.

How to convert MBR to GPT disk in Windows 10

GPT does not have the limitations of its predecessor, therefore it supports an almost infinite number of sections. GPT contains images of partitions and boot files in different places. Therefore, the system is more stable, and even if these files are overwritten or damaged, there will be no serious problems. GPT also supports the cyclic redundancy check function, which analyzes data for damage. Overall, GPT provides better performance. There is also a hardware limitation, and if you use the BIOS instead of UEFI, it will not be possible to boot from GPT. GPT also requires 64-bit Windows 10, 8, 7 or Vista.

Without saving data

There are several ways to convert HDD partitions without saving data.

Using Diskpart

Diskpart is a powerful tool that can help you convert an MBR partition to GPT on Windows 7, 10 and others. The software will delete all files and folders from the hard disk, therefore it is strongly recommended to create backup copies of important files. To convert do the following:

  1. Win + X and click "Command Prompt" (as administrator). If the function is not available, you can use PowerShell.
  2. In the window that opens, type diskpart and press Enter.
  3. Type list disk and press Enter. A list of all HDDs on the PC appears. If only one drive is installed, you will not be able to convert it when logging into Windows.

  4. Enter select disk X. Replace X with the correct HDD number above. It is extremely important to choose the right drive, so be careful. If you select the wrong disk, all data will be lost, so we advise you to weigh everything twice. One of the easiest ways to choose the right HDD is to check its size. If you have two or more hard drives, you can easily distinguish them by size.
  5. Now type clean and press Enter. After running this command, all files from the hard will be deleted, so be sure to create copies of all important documents.
  6. Type convert gpt and press Enter.

After that, the selected hard drive will be converted from MBR to GPT. Once again, we note that Diskpart is a very powerful tool, so keep in mind that you use it at your own peril and risk.

Diskpart during Windows installation

If you need to convert MBR to GPT, you can easily do it with Diskpart. To do this, follow these steps:

  1. Boot the computer from the installation media.
  2. Select the desired language and click Next.
  3. Click “Repair your computer” in the lower right corner.
  4. Select Troubleshoot - Advanced options - Command line (Troubleshoot - Advanced options - Command Prompt) and select your username. If necessary, enter your password.
  5. After starting the command line, follow the steps from the past method to start and use Diskpart.

You can immediately launch a command prompt when installing Windows using the Shift + F10 keyboard shortcut. This method is similar to the first solution, but by running Diskpart outside of Windows, it is possible to convert even the partition with the system. Diskpart will delete all files from the selected HDD, so be careful when using this method. Note that you do not need to use installation media to run the command line outside of Windows. The easiest way to do this is to open the “Start” menu, press the “Power” button, press and hold the Shift key and select “Restart” from the menu. Now you just need to go to the Troubleshooting section - Advanced options - Command line. After that, you can run the command line and use Diskpart without any problems.

Convert disk when installing Windows

The computer can automatically convert a disk from MBR to GPT when installing Windows. You need to load the installation media in UEFI mode, after which the disk will be automatically converted to GPT. To do this, follow these steps:

  1. Download the installation media in UEFI mode.
  2. You will be prompted to select the type of installation. Select Custom.
  3. Select all sections of your HDD and click "Delete." This will delete all files from the hard drive, so be sure to back them up. After deleting all partitions, you will see one large area of ​​unallocated space.
  4. Select unallocated space and click Next.
  5. Follow the instructions to complete the setup.

This method is useful if you are installing Windows on a brand new computer or you want to reinstall the system and convert the main HDD. The method is quite simple, but to use it, you must have UEFI support and download the installation media in UEFI mode.

Using Disk Management

A more convenient way for an ordinary user to convert MBR to a GPT-drive is using a graphical interface of the system. To do this, run Disk Management and convert HDD. You can do this as follows:

  1. Press the Windows key + X and select "Disk Management".
  2. When Disk Management opens, a list of all HDDs and partitions on the PC will appear. Before you convert a disk to GPT, you must delete all files and partitions. To do this, right-click the desired section and select "Delete." Repeat this step for all sections.
  3. After deleting all partitions, right-click on your HDD and select “Convert to GPT disk” in the menu.

Keep in mind that the method cannot convert the system disk while running Windows. This solution is also quite quick and simple, and if you prefer to use a graphical interface, be sure to try it. In this case, all your files from the hard drive will be deleted, so be sure to back up in advance.

No data loss

You can also convert hard disk partitions without deleting data in several ways.


In most cases, the conversion process will delete all files from the disk. Windows 10 Creators Update brought a new tool called MBR2GPT, which allows you to convert a disk without deleting files. To use it, follow these steps:

  1. Navigate to the advanced launch. To do this, open the "Start" menu, press the "Power" button, hold down the "Shift" key and click "Restart".
  2. A list of options will open. Open "Troubleshooting" - "Advanced options" - "Command line". Choose your account and enter your password.
  3. In the command prompt that opens, type mbr2gpt / validate.
  4. If there are no errors, type mbr2gpt / convert and press Enter. After executing this command, the disk will be converted from MBR to GPT.

It is not recommended to use this tool, as you may encounter various problems. To use it in the Windows environment, add / allowFullOS after each command:

  • mbr2gpt / validate / allowFullOS
  • mbr2gpt / convert / allowFullOS

Here you can immediately specify which disk to convert - with the command / disk: X. For example, if you want to convert the first hard drive, type:

mbr2gpt / convert / disk: 1.

Using MiniTool Partition Wizard

MiniTool Partition Wizard can help users convert an MBR disk containing Windows to GPT. Download software can be from the site developers.

IMPORTANT. If you are dealing with a system disk, in advance in case of any accidents after conversion:

  • Create a bootable media MiniTool Partition Wizard.
  • Create a system image or backup of your entire hard disk.

To successfully boot from a GPT disk, the system must support UEFI mode. Run the program and follow the instructions:

  1. Select the MBR disk you want to convert.
  2. Select “Convert MBR disk to GPT disk”:
    • In the list on the left, select "Convert Disk."
    • Select it in the drop-down list of the "Disc" menu above.
    • Right-click on the desired disk and select “Convert” in the pop-up list.
  3. Click the "Apply" button to perform the scheduled operations.
  4. In the pop-up window, select “Yes” to start converting the disk from MBR to GPT.
  5. At the end, click "OK".

How to fix through Legacy mode

There is another way to solve the problem of MBR, in which the installation of Windows is impossible - through the BIOS:

  • as soon as a welcome window appears with the name of the motherboard, quickly press Del or F2 until the BIOS settings menu opens;
  • Use the arrow keys on the keyboard to select the Boot tab;
  • Find the Boot Mode option here, select it and press Enter;
  • In the menu that opens, change the boot type from UEFI to Legacy or CSM (Compatibility Support Mode).

If you did not install Windows 7, 8 or 10 due to an error in the MBR table, this method will simply allow you to ignore it. Different firmware versions of motherboards have different BIOS versions, so in very rare cases menu items may differ. If you are not sure, it is better to use the instructions for your motherboard. You can download it on the manufacturer's website.