How to Check MBR or GPT in BIOS

This guide shows you how to determine whether your hard drive or SSD uses the MBR (Master Boot Record) or GPT (GUID Partition Table) partitioning scheme directly from your computer’s BIOS/UEFI firmware. Knowing this is useful before installing an operating system, converting disks, or troubleshooting boot issues. You’ll need access to your BIOS setup utility, which usually requires pressing a key like Del, F2, or F10 during startup.

What You’ll Need

Access to your computer’s BIOS/UEFI setup (no special tools required).
Your computer’s manual or a quick web search for the correct BIOS key if you’re unsure.

Step-by-Step

Restart your computer. If it’s already on, save any work and reboot.
Press the BIOS key repeatedly as soon as the screen goes black or the manufacturer’s logo appears. Common keys are Del, F2, F10, F12, or Esc. The exact key is often shown briefly on the boot screen (e.g., “Press F2 to enter Setup”).
Enter the BIOS/UEFI interface. You’ll see a menu system with tabs or icons. If you’re in “EZ Mode” or a simplified view, look for a toggle to switch to “Advanced Mode” (often by pressing F7 or a similar key).
Navigate to the storage or boot settings. Look for tabs or sections named Boot, Storage, Configuration, or Advanced. The exact wording varies by motherboard manufacturer (e.g., ASUS, MSI, Gigabyte, Dell, HP).
Find the disk information. Within the storage or boot section, you should see a list of connected drives (e.g., “SATA Port 0: Samsung SSD 860 EVO”). Select a drive to view its details, or look for a submenu like “Storage Information” or “SATA Configuration.”
Look for the partition style. The BIOS may display “Partition Scheme,” “Partition Table,” “MBR,” or “GPT” next to the drive. On some systems, you may need to check the “Boot Mode” setting: if it’s set to UEFI, the drive is likely GPT; if set to Legacy or CSM (Compatibility Support Module), it’s likely MBR. However, this is not a guarantee, so look for explicit wording.
If you see a list of boot options (e.g., “UEFI: Samsung SSD 860 EVO” vs. “Samsung SSD 860 EVO”), the UEFI entry usually indicates GPT, while the non-UEFI entry indicates MBR. This is a common indirect indicator.
Exit without saving when done. Press the key for “Exit” (usually Esc or F10), choose “Exit Without Saving,” and confirm. This prevents any accidental changes.

Common Mistakes

Confusing boot mode with partition style. A UEFI boot mode does not automatically mean the disk is GPT, and Legacy mode doesn’t always mean MBR. Always look for the explicit partition table type if available.
Changing settings accidentally. While browsing, you might toggle a setting like “Boot Mode” or “CSM Support.” If you don’t intend to change anything, exit without saving to avoid boot issues.
Looking in the wrong section. Some BIOS versions hide disk details under “Advanced” > “SATA Configuration” or “Storage Configuration,” not under the main “Boot” tab.
Assuming all drives are shown. If you have multiple drives, make sure you’re checking the correct one. The BIOS may only display drives that are currently connected and detected.

Tips

Check the boot mode first. If your BIOS shows “Boot Mode: UEFI” and “Boot Mode: Legacy/CSM,” note which is active. Then cross-reference with any drive-specific info.
Use the search function. Many modern BIOS interfaces have a search bar (often opened with F9 or Ctrl+S). Type “partition” or “GPT” to jump directly to relevant settings.
Take a photo. Use your phone to photograph the BIOS screen showing the disk details. This can help you compare with online guides or remember the information later.
If you can’t find it in BIOS, check Windows or Linux. You can always verify the partition style from within the operating system (e.g., using Disk Management or `diskpart`), which is often more straightforward.

Troubleshooting

You can’t enter BIOS. Try restarting and pressing the key more rapidly, or use the Windows recovery menu: go to Settings > Update & Security > Recovery > Advanced startup > Restart now, then choose Troubleshoot > Advanced options > UEFI Firmware Settings.
You don’t see any drive information. This can happen on older systems or when the drive is not detected. Check that the drive is properly connected. If it’s an internal drive, reseat the cables. If it’s an external drive, it may not be shown in BIOS; connect it internally or use a different method.
The BIOS shows “MBR” but you expected GPT (or vice versa). This is possible if the drive was converted or if you’re looking at the wrong drive. Double-check the drive model and capacity. If you need to convert, use a tool like Windows Disk Management or `diskpart` (back up data first).
Your BIOS is very old and only shows a text-based interface. Older BIOS versions may not display partition style at all. In that case, rely on the boot mode indicator or check from within the OS.
You made changes and now the system won’t boot. If you accidentally changed a boot setting, re-enter BIOS and restore the previous configuration, or load “Optimized Defaults.” If that fails, use the motherboard’s Clear CMOS jumper or button (refer to your manual).

Frequently Asked Questions

Can I check MBR or GPT without entering BIOS?

Yes. In Windows, open Disk Management (right-click Start > Disk Management), right-click the disk (e.g., Disk 0), and select “Properties.” Go to the “Volumes” tab; the “Partition style” will show either “Master Boot Record (MBR)” or “GUID Partition Table (GPT).” In Linux, use `sudo parted -l` or `lsblk -o NAME,PARTTYPENAME`.

Is GPT better than MBR?

GPT is generally more modern and supports disks larger than 2 TB, as well as more than 4 primary partitions. MBR is older and has limitations. For UEFI-based systems, GPT is recommended, but MBR still works fine for legacy boot.

Does checking in BIOS change anything?

No, simply viewing the information does not alter the partition table. However, if you change settings like boot mode, you can affect how the system boots.

Why does my BIOS show “UEFI” but the disk is MBR?

This can happen if the system is configured to boot in UEFI mode with CSM (Compatibility Support Module) enabled, allowing legacy MBR disks to boot. The partition style is independent of the boot mode in such setups.

Can I convert MBR to GPT from BIOS?

No, BIOS firmware cannot convert partition styles. You must use an operating system tool like Windows Disk Management (which requires deleting all partitions) or a third-party partition manager. Always back up your data first.

What if my BIOS doesn’t show any partition info?

This is common on older systems. Use the operating system method instead. If you need to know before installing an OS, you can boot from a live Linux USB and use `gdisk` or `parted` to check.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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