What CSM is and why you might disable it

CSM (Compatibility Support Module) is a feature in your computer's BIOS that lets older programs and operating systems run on newer hardware. It acts as a translator between old software and new motherboards. Most computers ship with CSM turned on by default.

You would disable CSM if you are installing a modern operating system like Windows 11 or a recent Linux distribution, or if you want to use UEFI (Unified Extensible Firmware Interface) — the newer standard that replaces the older BIOS boot method. Disabling CSM can also slightly improve boot speed and reduce security vulnerabilities, since CSM mode is older and less protected than UEFI-only mode.

The tradeoff is that with CSM off, you cannot run very old software or boot from older installation media. If you need to run legacy programs or use hardware from before 2010, you should leave CSM on.

Key Takeaways

  • CSM is a compatibility layer that lets old software run on new hardware, and disabling it forces your computer to use the newer UEFI standard instead.
  • You access the CSM setting in your BIOS setup menu, which you enter by restarting your computer and pressing a specific key during startup — usually Delete, F2, F10, or F12 depending on your motherboard brand.
  • The exact location of the CSM setting varies by manufacturer: look for it under names like "Boot", "Advanced", "Integrated Peripherals", or "Onboard Devices".
  • After you disable CSM, you must also ensure your hard drive is formatted as GPT rather than MBR, or your operating system will not boot.
  • If your computer will not start after disabling CSM, you can turn it back on by entering BIOS setup again and reversing the change.

How to enter BIOS setup on your computer

To reach the CSM setting, you first need to enter your BIOS setup menu. Shut down your computer completely, then turn it back on. As soon as the screen lights up, begin pressing a specific key repeatedly — do not wait for the operating system to load.

The key you need depends on your motherboard manufacturer. For most computers, it is Delete or F2. Some Dell machines use F2, some HP machines use F10, and some Lenovo machines use F1 or F2. Asus boards often use Delete. If you are unsure, restart and watch the first screen carefully — it usually displays a message like "Press Delete to enter Setup" or "Press F2 for BIOS".

If you miss the window, your operating system will start loading. Shut down again and try once more, pressing the key faster this time. You will know you are in BIOS when you see a blue or gray menu with white text, not your normal desktop.

Finding CSM in different BIOS menus

Once you are in BIOS setup, the location of the CSM setting depends on your motherboard brand. There is no single standard location, so you may need to look in several places.

On Asus boards, look in the "Advanced" tab at the top, then find "System Agent Configuration" or "Onboard Devices Configuration". CSM is sometimes labeled "Launch CSM" or "Compatibility Support Module".

On MSI boards, go to "Settings" or "Advanced", then look for "Boot" or "Integrated Peripherals". The setting may be called "CSM" or "Legacy ROM".

On Gigabyte boards, check "BIOS Features" or "Integrated Peripherals" under the main menu. It is often near other boot-related settings.

On Intel NUC or OEM systems (Dell, HP, Lenovo), the setting might be under "Boot Options", "Security", or "Advanced". Some manufacturers hide it under "Secure Boot" settings.

If you cannot find it after checking these sections, use the search function if your BIOS has one — many modern BIOS menus let you press Ctrl+F to search for "CSM" directly.

Disabling CSM step by step

Once you locate the CSM setting, the process is straightforward. Highlight the line that says "CSM", "Launch CSM", "Compatibility Support Module", or "Legacy ROM" using your arrow keys. The current value will show either "Enabled" or "Disabled".

Press Enter or the right arrow key to change the value to "Disabled". Some BIOS menus let you press Y or N instead. You will see the setting flip to "Disabled".

After you change it, navigate to the "Save and Exit" option, usually at the bottom of the menu or in a separate tab. Press Enter and confirm that you want to save changes. Your computer will restart.

Do not be alarmed if your computer takes longer to boot the first time after this change — it is reconfiguring how it starts up. This is normal and should only happen once.

Checking your hard drive format before disabling CSM

Before you disable CSM, you should verify that your hard drive is formatted as GPT (GUID Partition Table) rather than MBR (Master Boot Record). If your drive is still in MBR format and you disable CSM, your operating system will not boot.

On Windows, right-click the Start menu and open "Disk Management". Find your main hard drive in the list, right-click it, and select "Properties". Click the "Volumes" tab. If it says "Partition style: GPT", you are safe to disable CSM. If it says "MBR", you need to convert it first or leave CSM enabled.

On Mac or Linux, open a terminal and type diskutil list (Mac) or sudo parted -l (Linux). Look for your main drive and check whether it shows "GPT" or "MBR" in the partition table column.

If your drive is MBR and you want to use UEFI without CSM, you will need to back up your data, convert the drive to GPT, and reinstall your operating system. This is a larger project — if you are not comfortable with that, leave CSM enabled.

What to do if your computer will not start after disabling CSM

If you disabled CSM and your computer now shows a black screen, will not boot, or displays an error message, the most common cause is that your hard drive is still in MBR format. The good news is that this is reversible.

Restart your computer and enter BIOS setup again using the same key you used before. Navigate back to the CSM setting and change it back to "Enabled". Save and exit. Your computer should boot normally again.

Once you are back in your operating system, you can either convert your drive to GPT (if you want to use UEFI) or simply leave CSM enabled (if you do not need UEFI). There is no performance penalty to leaving CSM on if your hardware and software support it.

When to leave CSM enabled

You should keep CSM enabled if you use older software, older external drives, or older installation media. If you have a printer, scanner, or other device that was made before 2012, it may only work with CSM on.

You should also leave CSM on if you are dual-booting an older operating system like Windows 7 or an older Linux distribution. Disabling CSM will prevent those systems from starting.

If you are unsure whether you need CSM, the safest choice is to leave it on. Modern operating systems work fine with CSM enabled, and you lose nothing by keeping it.

Frequently Asked Questions

Will disabling CSM make my computer faster?

Disabling CSM may reduce boot time by a second or two, but the difference is usually not noticeable in everyday use. The main reason to disable it is to use UEFI security features like Secure Boot, not for speed.

Can I disable CSM if I have Windows 10?

Yes. Windows 10 works with both UEFI and CSM. However, your hard drive must be formatted as GPT for UEFI to work. If your drive is MBR, you can either leave CSM on or convert the drive to GPT and reinstall Windows.

What is the difference between CSM and Secure Boot?

CSM is a compatibility layer for old software. Secure Boot is a security feature that verifies the operating system before it starts. You can have Secure Boot on with CSM enabled, or Secure Boot on with CSM disabled. Disabling CSM lets you use Secure Boot more effectively.

If I disable CSM, can I still use USB drives to boot?

Yes, as long as the USB drive is formatted as UEFI-bootable. Most modern installation media for Windows 11 and recent Linux distributions are UEFI-bootable by default. Older USB drives made for Windows 7 or earlier may not work without CSM.

Do I need to reinstall my operating system after disabling CSM?

Not always. If your drive is already in GPT format and your operating system was installed in UEFI mode, disabling CSM should work without reinstalling. If your drive is MBR or your OS was installed in legacy mode, you will need to convert the drive or reinstall.