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 Commonly caused by unstable hardware overclocking, outdated CPU microcode, or incompatible RAM memory blocks.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. Use instructions for your exact device and software version. If Windows cannot start, see the startup guide.

Work through these checks

0 of 4 complete
01Reset BIOS configuration to stock defaults
  1. Reset BIOS configuration to stock defaults
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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02Disable XMP/EXPO memory profiles in UEFI
  1. Disable XMP/EXPO memory profiles in UEFI
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
03Flash motherboard BIOS to the latest version
  1. Flash motherboard BIOS to the latest version
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
04Run RAM diagnostics overnight using MemTest86
  1. Run RAM diagnostics overnight using MemTest86
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

  • 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  • Outdated motherboard BIOS firmware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 changes before applying them.

mdsched.exe