Windows & BSOD · critical

How to fix0x00000078

PHASE0_EXCEPTION (0x78)

What this error means

0x00000078 shows up as a critical-severity Windows operating system fault. An unhandled exception occurred during the early boot phase (Phase 0 initialization). Commonly caused by unstable hardware overclocking, outdated CPU microcode, or incompatible RAM memory blocks. It sometimes comes down to CPU core voltage instability or sag. Work through the steps below in order.

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
01Reset BIOS configuration to stock defaults

Reset BIOS configuration to stock defaults.

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

I need help
02Disable XMP/EXPO memory profiles in UEFI

Disable XMP/EXPO memory profiles in UEFI.

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

I need help
03Flash motherboard BIOS to the latest version

Flash motherboard BIOS to the latest version.

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

I need help
04Run RAM diagnostics overnight using MemTest86

Run RAM diagnostics overnight using MemTest86.

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

I need help

Possible causes

  • CPU core voltage instability or sag
  • Processor microcode out of sync
  • Unstable memory timing configuration (XMP)
  • Outdated motherboard BIOS firmware

Useful Windows tools

These commands open Windows tools. Review any action inside the tool before applying changes.

mdsched.exe