Windows · Windows Server  ·  critical  ·  Core Windows faults

STOP 0x00000124 — WHEA_UNCORRECTABLE_ERROR

The hardware itself reported an error it could not correct. This is a hardware fault report, not a Windows fault.

What you see

Sudden bugcheck with 0x124, often under load. Event Viewer records a WHEA-Logger event in the System log at the same moment.

What is actually wrong

CPU, memory controller, PCIe bus or power delivery. Overclocking and undervolting produce this readily; so do failing VRMs, an inadequate PSU, and heat.

Codes and articles

0x000001240x124WHEA_UNCORRECTABLE_ERROR

Fixes (2)

Return everything to stock and retest
Firmware setup30 minutes plus testinglow riskreversible

Any non-default voltage, clock or memory profile is in play. Do this before anything else — it costs half an hour and settles the question.

  1. Enter firmware setup and load optimised defaults.

  2. Leave XMP/DOCP/EXPO OFF for now.

  3. Disable any vendor undervolt or performance utility in Windows — these reapply their settings at every boot.

  4. Run the machine under the load that used to crash it for a full day.

Confirm it workedNo WHEA events under load.
PowerShell
Get-WinEvent -FilterHashtable @{LogName='System'; ProviderName='Microsoft-Windows-WHEA-Logger'} -MaxEvents 20 | Format-Table TimeCreated, Id, Message -AutoSize
If you need to undo itReapply the profile one setting at a time if you need the performance, retesting between each.
Read the WHEA record and narrow the component
Elevated PowerShell1 hourlow riskreversible

Everything is stock and it still happens.

  1. Read the WHEA events — they name the error source, which narrows it to processor, memory or PCIe.

    PowerShell
    Get-WinEvent -FilterHashtable @{LogName='System'; ProviderName='Microsoft-Windows-WHEA-Logger'} -MaxEvents 20 | Format-List TimeCreated, Id, Message

  2. Check temperatures under load with HWiNFO64. Sustained CPU temperatures at the thermal limit are a common cause.

  3. Reseat the RAM and the GPU, and check the CPU cooler is properly mounted.

  4. If the error source is PCIe, remove add-in cards one at a time.

  5. Update the motherboard firmware — CPU microcode ships in it, and microcode bugs surface exactly like this.

  6. Test with a known-good power supply if the machine is more than a few years old.

Confirm it workedThe machine runs its previous workload without WHEA events.
If you need to undo itNone — these are diagnostic steps.

Reference

Bug Check 0x124 — Microsoft Learn ↗

Related faults

0xC000021A — STATUS_SYSTEM_PROCESS_TERMINATEDWindowsSTOP 0x0000009F — DRIVER_POWER_STATE_FAILUREWindowsSTOP 0x000000EF — CRITICAL_PROCESS_DIEDWindowsSTOP 0x00000139 — KERNEL_SECURITY_CHECK_FAILUREWindowsSTOP 0x0000001E — KMODE_EXCEPTION_NOT_HANDLEDWindowsRandom crashes and corruption — testing for bad memoryWindows

Where this stops. This write-up was written and checked by hand. It says what each step changes, how to confirm it worked and how to reverse it, and anything destructive is flagged before you reach it. If it does not match what your machine is doing, search the Support Centre for the exact code or message — and when something needs a person, get in touch.