Removing gpt. Windows cannot be installed on this disk - GPT partition style

When installing an operating room Windows systems on a computer, some users are faced with the need to convert GPT to MBR. For example, in a situation where during system installation a message appears stating that the system cannot be installed on HDD having a GPT partition style. One solution to this problem is to convert the GPT partition table to MBR.

For quite a long time, computers used the master boot record - MBR (Master Boot Record). While loading operating system The BIOS initializes the computer's hardware, accesses the master boot record, and then transfers control to the operating system.

Modern hard disks by default they have a GPT partition style, which replaced MBR. GPT (GUID Partition Table) - the GUID partition table is part of the UEFI (Unified Extensible Firmware Interface), which is gradually replacing the outdated BIOS on computers. Read here how to find out the disk installed on your computer.

Why is it necessary to convert a GPT disk to MBR?

Over time, new technologies appear, so the usual BIOS has been replaced by UEFI, which implements a different technology for initializing and transferring the boot of the Windows operating system. Specifically, UEFI has Secure Boot Secure Boot.

Manufacturers hard drives began to produce products with a GPT table that support new interface BIOS. GPT disks have some differences from MBR disks.

The main differences between GPT and MBR disks for ordinary users are:

  • disks with MBR are limited in size up to 2 TB and in the number of partitions on the disk up to 4 partitions;
  • GPT disks support 128 partitions and much larger sizes hard drive;
  • 32 cannot be installed on a GPT disk bit version Windows;
  • GPT disks for installing Windows are used only with UEFI BIOS.

The user can independently decide in which situations it would be preferable to use one or another hard drive layout option.

For example, you have quite weak computer, so using 64-bit Windows instead of 32-bit does not make sense due to the fact that you will not get any benefits, and in most cases, the x64 system will eat up more system resources. To install or reinstall an operating system on a disk with an MBR, any bootable Windows flash drive. In the case of a GTP disk, there are some nuances that may prevent you from booting from USB flash drives and install the OS.

In this article, we look at how to change the GPT partition style to an MBR master boot record. In other situations, on the contrary, it will be required.

In the instructions, I will tell you how to change GPT to MBR using the Windows operating system: using the Disk Management snap-in and command line. Change GPT to MBR system means is possible only with loss of data on the disk, including on all logical partitions of this disk.

There are ways to translate HDD drive from GPT to MBR without data loss. For this purpose, a third party is used software(Acronis Disk Director, Paragon Hard Disk Manager, AOMEI Patition Assistant, EaseUS Partition Master, MiniTool Partition Wizard, etc.) launched from bootable media.

Converting GTP to MBR using system tools becomes possible if there are no partitions with data on the disk. Therefore, you must first delete all partitions on your hard drive and then proceed to converting partition tables. All information will be lost.

How to convert GPT to MBR from Disk Management

Directly from the operating system, you can change GPT to MBR from the Disk Management snap-in. To do this, follow these step-by-step steps:

  1. Press the “Win” + “R” keyboard keys at the same time.
  2. In the “Run” window, in the “Open” field, enter the command: “diskmgmt.msc” (without quotes), click “OK”.
  3. In the Disk Management window, click right click mouse by the name of the disk, in the place where the names of the local disks are located: “Disk 0”, “Disk 1”, etc.
  4. If there is data on the disk, the context menu item “Convert to MBR disk” will be inactive. To activate the conversion feature, you must delete data from the disk.
  1. Right-click on the disk location and select “Delete Volume...”.
  2. After cleaning the disk, click on the disk name and select “Convert to MBR disk.”

  1. Complete the necessary steps.

Once the GPT to MBR conversion is completed, you will have a hard drive that supports the Master Boot Record (MBR). Now on this disk can be installed Windows any bit depth.

How to convert GPT to MBR when installing Windows on the command line

The user can change GPT to MBR directly during installation of the Windows operating system. We will convert GPT to MBR when installing Windows 10. In Windows7, Windows 8, Windows 8.1 operating systems, similar steps are performed.

During the installation of the operating system, an error message will appear in the window for selecting a partition for installing Windows: “Windows cannot be installed on partition X of drive X. (Show details).”

There are three options to solve the problem:

  • use that supports installation in UEFI and GTP;
  • deleting all partitions on the disk during Windows installation; when the installation continues, the system will automatically create a suitable partition style;
  • during Windows installation, use conversion from GPT to make an MBR disk (our case);

The command line will help us convert a disk from GPT to MBR.

In the Windows installation window, press the “Shift” + “F10” keys (on some laptops it may be “Shift” + “Fn” + “F10”).

A console will open in which you need to execute sequential commands. After entering each command, press the Enter key.

Enter the command to launch the Diskpart utility for working with disks:

Diskpart

The following command shows a list of drives:

List disk

Then you need to select the disk number from the list of physical disks on the computer on which you want to install Windows. A computer may have multiple hard drives. When choosing a disk, be guided by the disk size.

Select disk X (X is the disk number)

Now you need to clean up the disk. All disk partitions and data will be deleted.

Enter the command to convert the disk to MBR format:

Convert mbr

After converting the disk is complete, enter the command to exit the Diskpart utility:

Close the console window.

The disk has been converted to MBR, you can continue installing Windows.

In the operating system installation window, click on “Update” to select a disk. The new location "Unallocated space on disk 0" appears.

Click "Create" and then the "Apply" button.

In the window that opens, you will see a message: “To ensure that all of its features work correctly, Windows may create additional partitions for system files" Click on the "OK" button.

The operating system has created a special partition (“System Reserved”). Select another size (it is larger) to install the system, click on the “Next” button.

Windows installation begins. Read detailed articles by following the links about installation,.

Conclusions of the article

If necessary, the user can convert the GPT disk partition scheme to MBR using system tools: the Disk Management snap-in and the command line, which can be used to convert the disk when installing the Windows operating system on a computer.

Style hard sections GPT disk provides more benefits than the legacy MBR standard for both the commercial sector, which uses equipment to store huge amounts of data, and ordinary users. Advantages of GPT disks for ordinary people - best performance and a high probability of recovering accidentally or accidentally destroyed data. If the computer motherboard supports the operating mode (an indispensable condition for working with GPT disks), but for some reason cause hard the disk with the formed partition structure and stored data has the MBR partition style, everything can be changed. Not without harm to the operating system, but with preservation of the disk structure and files on non-system partitions. Windows will still have to be reinstalled. Of course, there is a way to do without reinstalling Windows, but it is complicated by the process of restoring the ability of the current operating system to boot. After all, you will have to manually create a recovery partition and an encrypted EFI partition (used instead of the “System Reserved” boot partition on the MBR disk), and then restore the UEFI system boot loader. When you reinstall Windows, all these issues will be resolved automatically. Plus, we will get a clean operating system without old operating errors.

So, below we’ll look at how to install Windows on a disk converted from MBR to GPT without losing data on non-system partitions. But first, let's talk about how Windows is installed on a GPT disk with the loss of markup and stored data.

1. Installing Windows on a GPT disk with data loss

Preserving the partition structure and data of an MBR disk does not always make sense. For example, when connecting hard disc purchased on the secondary market. What to do in this case? Since BIOS UEFI only works with GPT disks, it is therefore necessary that this firmware operating mode is active, and the Windows installation process is carried out from a UEFI bootable USB flash drive. We will return to these points when we consider how to install Windows on a GPT disk without losing data and partitions. But if the hard drive was initially initialized as MBR, then during the Windows installation process with the BIOS UEFI interface enabled, we will receive the following notification.

What can I do to make it possible to install Windows on a GPT disk? You need to completely delete all partitions on your hard drive...

And install the operating system on unallocated disk space. Or, using the “Create” button, create several partitions on the disk in order to indicate only one of them as the installation location for the system, and use the rest as file storage.

During installation Windows hard the disk will be automatically converted to GPT.

This is a way to install Windows on a GPT disk, losing the partition structure and stored data. But what if the MBR disk is filled with information, and there is a lot of it? Even if there is somewhere to temporarily transfer important data - to another hard drive or removable media, with large volumes, the procedure for transferring files back and forth will take time. If there is nowhere to temporarily place the data, there is only one way out - converting the disk from MBR to GPT and then reinstalling Windows to the system partition.

2. Preparatory stage

Before you begin the conversion process, you need to check a few things and prepare your working tools. Need to:

  • Make sure that the BIOS actually supports the UEFI interface;
  • Write down bootable USB flash drive UEFI with the installation process of 64-bit Windows 7, 8.1 and 10 (done using the Rufus program or the utility for downloading the distribution kit for versions of the system 8.1 and 10 Media Creation Tool);
  • Save important data of the current Windows, in particular, files in user profile folders, export settings of important programs, extract license keys and perform other actions as before the normal process of reinstalling the operating system;
  • Download from the official website and install the AOMEI Partition Assistant program on your computer (in the current Windows on an MBR disk), with the help of which the process of converting the hard drive from MBR to GPT will be carried out. The program can be downloaded in the free Standard Edition; among other functionality, it provides the ability to convert disk partition styles.

3. Converting a disk from MBR to GPT

Having carried out all the steps listed above and prepared the necessary tools, launch AOMEI Partition Assistant. In our case, in the program window we will see two hard drives computer: one of them has already successfully completed the conversion procedure from MBR to GPT, while the other, an MBR disk, has yet to undergo it.

On an MBR disk we call context menu, select the “Convert to GPT disk” command, then in the confirmation window for starting the operation, click “OK”.

A software window will appear with advice before starting the operation to make sure that the motherboard supports the BIOS UEFI operating mode. This window also informs you that if the converted disk is bootable and has an operating system installed on it, the latter will no longer be able to boot after the operation is completed. This is why it is important to take seriously preparatory stage operations and perform all the actions recommended in the previous paragraph of the article. Click “Yes”.

At the top left of the window, click the “Apply” button.

Clicking “Yes” is the point of no return, the current Windows will no longer be able to boot as the hard drive will be converted to GPT upon completion of the operation. The completion of the operation will be notified by such a program window, in which the only possible action will be to click “Ok”.

Before clicking “Ok”, check whether the UEFI bootable USB flash drive with the installation installation is connected Windows process. After clicking “Ok” the computer will reboot.

4. BIOS UEFI setup

The next time you start your computer, you must immediately enter the BIOS to set the UEFI operating mode. IN Motherboard BIOS Asus boards this is done as follows. In the main menu, press either the “ Additional settings", or the F7 key.

By clicking “Ok” we confirm entering the advanced mode. Go to the “Download” tab, then select the “CSM” section (it must be enabled, that is, the value “Enabled” should appear opposite it). In the “Boot device parameters” column, set the value to “UEFI and Legacy UpROM” - a compatibility mode that allows booting in both UEFI and Legacy modes. Then use the “Back” button to exit the section settings.

If you are installing Windows 7 on your computer, you also need to (Secure Boot) - go to the “Secure Boot” section and in the “OS Type” column set the value to “Other OS”. And go up a level with the “Back” button.

In the list of boot devices, select the UEFI bootable USB flash drive.

We save the changes made to the BIOS: press the F10 key and select “Yes”.

In the BIOS of other motherboards, the settings will be different. But their essence will be reduced to the same thing as described for motherboard Asus:

  • Setting the UEFI operating mode (or compatibility mode, if supported, as in the example discussed);
  • Disable secure boot for operating systems that do not comply with UEFI standard certificates;
  • Setting boot priority from a UEFI flash drive;
  • Saving settings.

5. Installing Windows on a GPT disk

After saving the BIOS UEFI settings, the computer will boot from the USB flash drive. We go through the initial stages of the installation process and will linger a little on choosing the installation location. In order for the data on non-system disk partitions to remain safe and sound, you need to delete only two partitions that were responsible for Windows startup– the first boot partition with a capacity of 350 or 500 MB (depending on the version of Windows) and the second partition on which the operating system itself was installed. To avoid mistakes, especially if there are several hard drives connected to the computer, it is better to focus on the size of the partitions. In our example, the disk just converted from MBR to GPT is identified by the Windows installation process as Disk 0. We first delete the first partition using the “Delete” button.

Then we repeat the procedure with the second section.

Click on the unallocated space created as a result of deleting partitions and click the “Next” button to continue the Windows installation process.

Have a great day!

Until Windows 8 appeared, computers used hard drive partitioning - MBR. Therefore, if instead of the established eight you try to put windows version older - she doesn't recognize new GPT interface. Therefore, a message will simply appear stating that Windows cannot be installed on this disk.

What does the error look like?

Older operating systems work with the MBR. This is special program code and the necessary information needed to start the system. They are located in first marked hard sector disk. AND starts MBR after checking the bioses of all PC components. The main function of the MBR is to find the files needed to run Windows.

GPT– a new type of format for placing tables on a hard drive. All because Intel decided give upBIOS and proposed a new interface - EFI, and the new format is part of it.

Installing Windows on a GPT partition

It is better to eliminate all the difficulties associated with installing the system on a HDD with existing GPT partitions using the data recommendations:

  1. Use 64 bit version of the system.
  2. UEFI must be in quality boot mode.

Often, the error occurs due to the second point. Namely, its complete ignoring. On modern computers There is no point in installing a 32-bit system. To correct the error, it is advisable to do setting BIOS, or prepare installation disk with the system so that it supports UEFI.

Setting up BIOS or UEFI

Installing one of latest versions Windows is a must check settings UEFI and BIOS. To do this you should clamp Hotkeys.

IN Windows 7 This Esc+F1+F2, depends on who the motherboard manufacturer is. If speak about Windows 8 , then you need to change settings related to system boot (Win+C).

To enter the settings UEFI in Windows 10 need to:

  1. Click to the notifications that are in the bottom panel and there we click “ Options”.
  2. Select “ Updates and Security”.
  3. Select “ Recovery partitions” - “Special methods of loading and rebooting.”
  4. After restart systems, you need to choose Extra options and UEFI settings.

The BIOS will turn on and you need tune its menu so that the new operating system is automatically installed on GPT disks. To do this change the load interface from CSM to UEFI.

Next you need change operating mode, select AHCI instead of IDE. The setting is in the section Peripherals or SATA Configuration.

Convert GPT to MBR during installation

If UEFI is missing or cannot be configured, you will have to change styles sections. This is done by means that are already built into the system, or by means of the operating system.

Important terms for those who have an old download interface - there should be nothing on the hard drive, or if there is nothing needed, then it is not necessary to delete it.

To change toMBR required:

  1. Installing system you will reach the point where you need to select the partition type, you should hold down the hot keys SHIFT+F10.
  2. Now enter commands like: discpart, then listdisk.
  3. When will it appear list sections, you should enter select diskX. X is the actual disk with which we perform the conversion.

Now you can delete everything by entering Clean. Last action– change of style, for this purpose enter convert mbr.

When the conversion is complete you will need:

  1. Register final command Exit.
  2. Close command line window.
  3. Produce disk partitioning into sections.
  4. Continue installation of the operating system.

Problems rarely occur, only if the hard drive is damaged.

Quite often, users are faced with what they think is a big problem when it becomes necessary to convert the partition style from GPT to MBR. This may be due to many factors, among which the main one is the impossibility of installing some OSes in such partitions and compatibility with the new standard of the UEFI primary input/output system, which replaced the BIOS. There are several ways to convert partitions with more modern GPT markup to MBR and vice versa. But you can replace one style with another either with or without saving the data. Let's consider each of these options, since some steps may be useful even when installing the operating system on your computer for the first time or reinstalling it.

Difference between GPT and MBR styles

First, let's look at what exactly is the difference between these styles, and what each of them can be used for. The MBR (with boot record) partitioning is considered to be obsolete today, and has been replaced by the new GPT style. This type of partitioning on a hard drive is mandatory if the hard drive has a capacity of 2 TB or more. But to ensure correct work with such partitions and use of their full capacity, you need an updated version of the primary system, designated UEFI.

If MBR and BIOS are used, installing disks of this size on modern computers becomes simply pointless, since the BIOS does not support them, and if the UEFI mode is disabled, despite the media being detected in the primary system, the full disk space will be inaccessible. So, think a hundred times to what extent it is advisable to perform the actions described below.

Problems with operating systems

But the main problem is that outdated operating systems like Windows 7, which are still popular among many users, are not installed on partitions with GPT partitions, and do not even support the main UEFI operating mode. To carry out the installation, some users suggest disabling UEFI to use Legacy mode, as for a regular BIOS. On the other hand, if you purchase new computer with the primary UEFI system already installed instead of the BIOS, G8 will not install with UEFI disabled either. Thus, we get two mutually exclusive factors. However, such obstacles can be overcome by using sufficient simple methods, but it will take a little effort.

Conversion during Windows installation

First of all, let's focus on whether to install Windows or vice versa. In this case, the safety of the data on the disk is not guaranteed, since it will have to be formatted during the installation of the operating system. Despite the fact that these questions are only indirectly related to the main topic, it does not hurt to have knowledge on them.

At one stage after starting the installation process, the installer of the same “seven” displays a message stating that installation to the selected partition is impossible. In this case, the simplest solution is to delete absolutely all partitions on the disk and install Windows in the unallocated area.

You can also create a system partition for Windows yourself, and use the rest of the space for logical volumes. However, this will not automatically create a special reserved partition, which will affect the fault tolerance of the installed OS. The installation section will be automatically converted to the desired style.

Thus, if we are talking about how to change GPT to MBR, you need to use the command line tools (Shift + F10), in which the following commands are written, shown in the image above. After this, you can continue installing the system as usual.

How to change GPT to MBR: creating a bootable USB flash drive and selecting the start mode of the primary I/O system

Now let's go back to the starting point and determine the steps that may be required to convert styles from an already installed OS (for example, Windows 8/1). To do this, you will initially need to create a bootable USB flash drive with Hard Disk Manager version 15 from Paragon or a similar utility from Acronis (Disk Director). The media itself is simply created in a small Rufus application, and then placed first among boot devices.

Immediately in the settings of the primary system, you must immediately change the boot mode (Boot Mode) from UEFI to Legacy and disable Secure Boot. Such actions are only necessary if a regular bootable flash drive was created for MBR, and not EFI.

Partition conversion process

Now you need to boot from the created media. The essence of how to change the GPT style to MBR comes down to deleting all partitions in the program at the first stage, including reserved by the system for recovery, leaving only the one on which the installed OS is located.

When deleting backup partitions, in the confirmation window, be sure to check the box to not request a volume label next time. Once these steps are completed, only the base GPT partition will remain. How to convert GPT to MBR at this stage?

To do this, you need to select the appropriate conversion item in the additional menu via RMB and confirm your actions. Since the operation will be transferred to the deferred category (as well as in other utilities like Acronis Disk Director), you need to click the “Apply” button, after which the conversion process will start.

Additional steps to create a backup partition

But that is not all. The fact is that after changing the style, the system simply will not boot, and besides, you need to create a backup partition for it with boot data of the installed OS itself with a volume of about 300 MB. This can be done through the RMB menu on an unallocated area and selecting the option to create a partition, after which you will need to specify its size and file system(NTFS), and after completing operations through the same menu, make the partition active.

Creating a configuration to boot the installed system

At the final stage, it remains to create a configuration so that the same “eight” could boot with the new partition style without problems. In this case, you need to restart the computer, boot from the installation media and call command console. In it you need to determine which letter is assigned to the active boot partition. To do this, first enter and then - lis dis, which will display all active sections.

We remember the drive letter on which the system is installed, execute the exit command for the main tool, and after it enter the line bcdboot N:\Windows, where N is the letter of the system partition. After that, we reboot the computer again, but in normal mode, setting the UEFI boot to normal, and rejoice. You can check the changed style directly through the partition properties on the volume tab.

Windows Tools

In principle, speaking of how to change GPT to MBR, one of the solutions for running OSes can be their own tool in the form of the disk management toolkit (diskmgmt.msc).

Here, too, you can delete unnecessary sections, and then through the RMB menu on the unallocated space, select the conversion from one style to another. True, the only and main limitation is that such actions can only be performed for non-system disks or logical partitions, that is, it will be impossible to change the style of a Windows disk directly in the system.

Changing section style using third-party programs

And finally, a few more words about how to change GPT to MBR. As more convenient tools than those available in Windows, you can use special disk programs from Acronis, AOMEI, Paragon and other developers. The operations performed, in general, do not differ much from those just described for Windows tools and boil down to converting unallocated space into the selected style. However, the conversion is much faster and more efficient. The interface of such programs is very similar to the control section Windows disks, but some operations (for example, redistribution disk space) are performed much easier by using the most common fader (slider), by moving which you can select the required dimensions of each section.

Brief summary

That's all briefly about style conversion. As is already clear, if we are talking specifically about performing transformations while preserving a working system and data that may be located specifically in system partition, you need to use only disk utilities with the preliminary creation of bootable media. If saving information is not required, you can convert both at the stage of reinstalling the OS and using Windows, and with the help third party programs. But you won’t be able to change the main partition in a running system even with their help, no matter how much you might want it. It will be impossible to remove it!

Good day everyone!

It sometimes happens that when you try to install Windows OS on your computer, you may see an error like: "Windows cannot be installed on this disk because the disk uses an MBR partition table. On EFI systems, Windows can only be installed on a GPT disk" . Or it is possible that your system simply does not see a disk larger than 2 TB.

In these cases, you need to convert MBR to GPT partition table to fix this problem. This can be done in different ways and ways, in this article I will look at how this can be done no data loss (see method 1 and 2)!

As a remark!

Difference between MBR and GPT. MBR supports partitions up to 2 TB. If your disk is, say, 4 TB (which is no longer uncommon), then when using MBR - 2 TB on such a disk will be listed as an unallocated area (and will not be used).

How to convert MBR to GPT

Method No. 1: step by step in the AOMEI Partition Assistant Standard Edition program

AOMEI Partition Assistant Standard Edition

Excellent and free program for working with hard drives. Allows you to literally change the file system, partition sizes, clone, etc. in just 2-3 clicks. Moreover, many operations are performed without loss of information (which is so lacking in the tools built into Windows).

Addition (from 11/10/18): the option for converting MBR to GPT in the 7th version of the program became paid (in the 6.6th version it was free, and it was this that I relied on when writing the article).

I don’t consider downloading and installing the program - it’s standard. After launching, in the main window of the program you can immediately find out which of the available disks in the system are in GPT and which are in MBR (see screenshot below).

As you noticed, "Disk 3" is MBR and I am converting it to GPT.

To do this, just right-click on the disk itself. (where it is directly written that this is “Disk 3”, see screenshot below), and select “Convert to GPT disk” in the menu that appears.

After that, in the left corner of the screen you need to confirm all the commands that we gave to the program in the current session: click the “Apply” button.

A reboot will be required to complete the current operation. Therefore, first of all, save all your open documents, and then click on the “Go” button in the program window (see example below).

The final touch: we agree to reboot...

After rebooting the device, instead of Windows boot special will be launched. conversion utility (see example below). Literally within a few seconds, my 1 TB disk was converted to GPT (I note again: without data loss).

That, in fact, is all the action.

Addition!

If you want to convert system disk(i.e. the drive on which you have Windows installed and from which you are in this moment loaded) - then you won’t succeed. In this case there are two options:

1) remove the disk from the PC/laptop, connect it to another device and perform the conversion operation;

2) create a bootable USB flash drive (can be done in the same AOMEI Partition Assistant Standard), and after booting from it, carry out the operation.

Make bootable CD, master

Method No. 2: using the MiniTool Partition Wizard utility

Multifunctional program for working with hard drives. Allows you to split, format, resize hard drive partitions. Free version The program supports conversion from MBR to GPT (which is what we need).

Perhaps one of the significant disadvantages for the majority will be the lack of Russian language.

Note: the screenshots in the article were made from version 10.3.

After launching the program, you will see a list of all drives connected to the system (HDD, SSD, USB flash drives, etc.). Please note that next to the disk name its partition table (MBR, GPT) is indicated.

To convert from one to the other: just right-click on to the desired disk and in the menu select "Convert MBR Disk to GPT Disk" (example in the screenshot below).

Then another warning will pop up, after confirming the operation - the disk will be converted. If you are converting a non-system disk (that is, not the one on which you have Windows installed), then the operation takes 1-2 minutes. (see screenshot below).

Method No. 3. From the command line or disk management

Important! This method will delete all your data on the disk!

If you encounter an error "On EFI systems, Windows can only be installed on a GPT disk" when installing Windows: then in order to open the command line, press the button combination Shift+F10.

In other cases, to launch the command line, open the task manager (key combination Ctrl+Shift+Esc) , press "file/new task" and enter the command CMD(check the box that the task must be completed as an administrator!).


Windows also has another good tool for working with disks. That's exactly what it's called - disk management .

To open it, you need:

  1. press a combination of buttons Win+R ;
  2. enter the command diskmgmt.msc and press Enter.

To find out what partition is on the disk (MBR or GPT), just right-click on the disk (in the place where it says “Disk 0”, “Disk 1”, etc., see the example below), and open properties .

  • "Partition table with GUID..." is GPT;
  • MBR markup will be explicitly stated.

To convert MBR to GPT - you must first completely delete all partitions on the disk (important! when deleting a partition, you will lose all data on the disk!) . If the partitions are not deleted, then the “Convert to GPT” button will simply not be active (as in the screenshot below).

That's all for me today.