Know if a hard disk / SSD is MBR or GPT

To reinstall Windows on a computer, the procedure is normally quite simple. For example, we can restore Windows 10 or start on a key USB in order to redo a clean installation of the operating system. But you may find yourself faced with an invalid disk error. In question, the recent Bios which imposes a type of disc type GPT instead of MBR .

This guide explains the few differences between MBR and GPT as well as a tutorial to see if your hard drive or SSD is of the type GPT or MBR .


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


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

See the type of disc GPT or MBR

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

menu demarrer gestion des disques

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

gestion des disques vue disque gpt mbr

3. The display is modified and a column indicates the””.  Partition type  “of each disk connected to the computer: MBR or GPT depending on the format of the hard disk / SSD .

gestion des disques vue disque gpt mbr

4. You can immediately see what type of partitions are configured on the machine’s disks. Disk 0″ normally corresponds to the main hard disk 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.

Conversion GPT / MBR

It is possible to convert a disc GPT in MBR and a disc MBR in GPT . Both operations require the complete deletion of the disk (formatting).