Firmware · medium

How to fixCSM-CONFLICT

CSM / Legacy Boot Conflict

What this error means

CSM-CONFLICT shows up as a medium-severity firmware fault. Compatibility Support Module (CSM) conflicts with UEFI OS or Secure Boot. It's also often linked to old OS installed in Legacy mode. See the troubleshooting steps below for the fix.

Before you begin

Save open work and back up important files. Note any recent driver or hardware changes. If Windows cannot start, use the startup guide first.

Work through these checks

0 of 3 complete
01Disable CSM for modern UEFI systems

Disable CSM for modern UEFI systems.

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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02Reinstall OS in UEFI mode

Reinstall OS in UEFI mode.

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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03Check Secure Boot compatibility

Check Secure Boot compatibility.

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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Possible causes

  • CSM enabled with UEFI OS
  • Old OS installed in Legacy mode
  • Secure Boot + CSM conflict