Know if a HDD / SSD is MBR or GPT

To reinstall Windows on a computer, the procedure is normally fairly straightforward. We can for example restore windows 10 Where boot from a USB stick in order to redo a clean installation of the operating system. But one may end up facing an invalid disk error. In question, the recent Bios which imposes a type of GPT disk instead of MBR. This guide explains the few differences between MBR and GPT, and a tutorial to see if your hard drive or SSD is GPT or MBR type.


The Master Boot Record (MBR) is the first boot sector of a hard drive. Vital information for the Bios to know what is on the disk and start the operating system. On Linux, the boot loader is called GRUB. Traditional hard disk (HDD) or SSD disk, no difference related to the type of disk. The same if the disc is internally connected to the computer or if it is connected via USB (external box or via a USB SATA adapter). The MBR size limitation is 2TB per disk.


GPT, for GUID Partition Table, is associated with UEFI type Bios. The 2TB limit drops and allows an unlimited number of partitions (Windows manages up to 128 partitions). On newer computers (Bios UEFI), the disk type is GPT. On the other hand, data disks can always be of the MBR type. HDD hard disk, SSD disk and USB flash drive can be in GPT format.

See the type of GPT or MBR disk

1. On Windows 10 and 8.1, do a right click on the start button and choose Disk management.

start menu disk management

2. A “Disk Management” window opens and does not yet display the desired information. Go to menu Display, High and List of discs.

disk management gpt mbr disk view

3. The display is changed and a column indicates the “ Type of partitions »Of each disk connected to the computer: MBR Where GPT depending on the format of the HDD / SSD.

disk management gpt mbr disk view

4. You can immediately see what type of partitions are configured on the disks of the machine. “Disk 0” is normally the primary hard drive of the PC, where the operating system is installed. The only difficulty will be to identify which disk it is, based not on the drive letter (Local disk C: for example) but on the displayed capacity.

GPT / MBR conversion

It is possible to convert a GPT disk to MBR and one MBR disk to GPT. Both operations require the entire disk to be erased (formatting).

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