Firmware · medium

How to fix CSM / Legacy Boot Conflict

Error code: CSM-CONFLICT

What this error means

Compatibility Support Module (CSM) conflicts with UEFI OS or Secure Boot. It's also often linked to old OS installed in Legacy mode.

Updated

Before you begin

Save open work and back up important files. Use instructions for your exact device and software version. If Windows cannot start, see the startup guide.

Work through these checks

0 of 3 complete
01Disable CSM for modern UEFI systems
  1. Disable CSM for modern UEFI systems
What to expect

Check whether the original symptom still occurs.

If it does not help

Continue only if this check applies to your device. Consult its manufacturer if you are unsure.

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02Reinstall OS in UEFI mode
  1. Reinstall OS in UEFI mode
What to expect

Check whether the original symptom still occurs.

If it does not help

Continue only if this check applies to your device. Consult its manufacturer if you are unsure.

Browse related errors
03Check Secure Boot compatibility
  1. Check Secure Boot compatibility
What to expect

Check whether the original symptom still occurs.

If it does not help

Continue only if this check applies to your device. Consult its manufacturer if you are unsure.

Browse related errors

Possible causes

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