What is GTP & MBR Partitions and How to Convert "GTP Partitions" into "MBR Partitions" Using CMD in Condition of Unable to Boot into Windows ?

Before Starting Converting GTP into MBR, Let's learn about GTP & MBR Partations

What is "GTP" Partition : 

          

          GUID Partition Table (GPT) is a standard for the layout of the partition table on a physical storage device, such as a hard disk drive or solid-state drive, using globally unique identifiers (GUID). Although it forms a part of the Unified Extensible Firmware Interface (UEFI) standard (Unified EFI Forum proposed replacement for the PC BIOS), it is also used on some BIOS systems because of the limitations of master boot record (MBR) partition tables, which use 32 bits for storing logical block addresses (LBA) and size information on a traditionally 512 byte disk sector.

          As of 2010, most current operating systems support GPT. Some, including OS X and Microsoft Windows on x86, support booting from GPT partitions only on systems with EFI firmware, but FreeBSD and most Linux distributions can boot from GPT partitions on systems with both legacy BIOS firmware interface and EFI.

What is "MBR" Partition :

          A Master Boot record (MBR) is a special type of boot sector at the very beginning of partitioned computer mass storage devices like fixed disks or removable drives intended for use with IBM PC-compatible systems and beyond. The concept of MBRs was publicly introduced in 1983 with PC DOS 2.0.

The MBR holds the information on how the logical partitions, containing file systems, are organized on that medium. The MBR also contains executable code to function as a loader for the installed operating system—usually by passing control over to the loader's second stage, or in conjunction with each partition's volume boot record (VBR). This MBR code is usually referred to as a boot loader.

The organization of the partition table in the MBR limits the maximum addressable storage space of a disk to 2 TiB (232 × 512 bytes). Approaches to slightly raise this limit assuming 33-bit arithmetics or 4096-byte sectors are not officially supported as they fatally break compatibility with existing boot loaders and most MBR-compliant operating systems and system tools, and can causes serious data corruption when used outside of narrowly controlled system environments. Therefore, the MBR-based partitioning scheme is in the process of being superseded by the GUID Partition Table (GPT) scheme in new computers. A GPT can coexist with an MBR in order to provide some limited form of backward compatibility for older systems.

MBRs are not present on non-partitioned media such as floppies, superfloppies or other storage devices configured to behave as such.

Now Let's Start Converting GTP into MBR in Condition of Unable to Boot into Windows.

Follow These Steps:-

1.   Insert Windows Installation Disc and Restart Computer.

2.   Boot from the installation media by Pressing Any Key at the “Press Any Key” screen.

3.   Now Go to System Recovery Options.

4.   Then Click On Command Prompt.

5.   Now Input the Command "diskpart" & Hit Enter.

6.   After that Input the Command "list disk" or "list volume" & Hit Enter.

7.   Please Remember the Number of the disk you want to Convert. For Example we have selected Disk No. 1

8.   Input Command "select disk 1" & Hit Enter.

      Here "1" is the No. of disk that is going to be converted.

9.   After that Input the Command "clean" & Hit Enter.

10.  Then Input the Command "convert mbr" & Hit Enter.

11.  Done. Disk Is Now Converted into MBR.

12.  Now You can Type the Command "exit" and hit Enter to exit.

                              OR

If you want to Continue Setting up Partitions on the new MBR disk then you can follow these steps.

1.   Input the Command "create partition primary" & Hit Enter.

2.   Input the Command "list volume" & Hit Enter.

NOTE: Please Make Sure that the New Volume is Selected Before you Format the Partition.

or You can select Volume Manually By the Command "select volume 'no. of volume' ".

3.   Then Input the Command "format fs=ntfs" & Hit Enter.

4.   Then Input the Command "exit" & Hit Enter to exit the Command Prompt.

                                               All Done.