Windows & BSOD · critical

How to fix0x00000100

LOADER_BLOCK_MISMATCH

What this error means

LOADER_BLOCK_MISMATCH is a critical-severity Windows operating system issue. A Loader Block Mismatch occurs when the boot loader (Winload.efi) passes a system parameters block to the Windows kernel that is incompatible or corrupted. Commonly caused by corrupted boot records, memory faults, or unstable overclocking. It's also often linked to failed storage driver installation. Follow the steps below to fix it.

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 4 complete
01Rebuild the Boot Configuration Data (BCD) using recovery USB

Rebuild the Boot Configuration Data (BCD) using recovery USB.

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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02Clear CMOS or disable XMP/EXPO memory profiles

Clear CMOS or disable XMP/EXPO memory profiles.

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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03Run Startup Repair from Windows Recovery

Run Startup Repair from Windows Recovery.

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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04Run SFC scan offline in Command Prompt

Run SFC scan offline in Command Prompt.

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

  • Damaged or corrupted EFI bootloader files (winload.efi)
  • Unstable memory overclocking (XMP/EXPO) or timing
  • Corrupted Windows registry system hive
  • Failed storage driver installation