WHEA_UNCORRECTABLE_ERROR: What It Means and How to Fix It

In this guide (10 sections)

• What exactly happens?
• Which part reported the error?
• 1. An overclock or automatic boost is pushing the processor too far
• 2. The memory profile (XMP or EXPO) is unstable
• 3. The BIOS is out of date
• 4. The processor has become unstable over time
• 5. The power supply can’t keep the voltage steady
• 6. The processor is overheating
• 7. Another part, such as the graphics card or an SSD, is reporting the error
• Real cases: what other users ran into

WHEA_UNCORRECTABLE_ERROR (stop code 124) means a part of the PC, almost always the processor, detected an error in its own work that it couldn’t correct, so Windows stopped. That sounds like broken hardware, but the usual reason is that the processor or RAM is being asked to run slightly beyond what’s stable: an overclockOverclocking: Running a part faster than its standard speed. More speed, but crashes if the part can't handle it. More in our Windows & performance glossary →Close ✕, an automatic boost setting, a fast memory profile or an old BIOS. Those are all things you can change for free. This guide goes from the most common cause to the least.

If you’re not sure which blue screen you have, start with our guide on how to find what caused a blue screen.

What exactly happens?

What you see	Most likely cause	Where to look
The crashes started after changing BIOS settings or tuning the processor.	An overclock or boost setting	Cause 1
The crashes happen while the PC is idle or doing light work, not in heavy games.	Too aggressive an undervolt, such as Curve Optimizer	Cause 1
The crashes started after turning on XMP or EXPO.	Memory speed too high for this PC	Cause 2
The PC has an Intel Core i7 or i9 of the 13th or 14th generation.	Old BIOS, or a processor that has become unstable	Causes 3 and 4
The PC was stable for months and is now crashing more and more often.	A part wearing out: processor or power supply	Causes 4 and 5
The crashes happen only after a long time under load, and the PC is hot.	Overheating	Cause 6
Event Viewer names “PCI Express” as the source of the error.	The graphics card, an SSD or an extension (riser) cable	Cause 7

Which part reported the error?

Windows records each hardware error in Event Viewer, and the record says which part reported it. It takes two minutes and saves a lot of guessing.

How to check:

1. Right-click the Start button and open Event Viewer.
2. Go to Windows Logs → System, then click Filter Current Log on the right.
3. In Event sources, tick WHEA-Logger and click OK.
4. Open the latest entries. “A fatal hardware error has occurred” is the crash itself; “A corrected hardware error has occurred” is a warning that was fixed on the spot. Each entry says which part reported it (“Reported by component”) and the type of error.

What it means: “Processor Core” as the component, or a “Cache Hierarchy Error”, points to the processor and its settings (causes 1 to 4). “Memory” points to the RAM (cause 2). “PCI Express” points to a card or SSD (cause 7). Many corrected errors with no crash are an early warning worth acting on too.

1. An overclock or automatic boost is pushing the processor too far

WHEAWHEA (hardware error report): The part of Windows that records errors reported by the hardware itself, mostly the processor. More in our Windows & performance glossary →Close ✕ errors appear when the processor makes a calculation error, and the most common reason is running it slightly faster, or at slightly lower voltage, than it can handle. That includes settings many people don’t know are on: some motherboards switch on automatic boost options by default, such as MCE (Multi-Core Enhancement) on Intel motherboards or PBO on AMD. UndervoltingUndervolting: Running a chip at slightly lower voltage so it makes less heat and noise, often with no loss of speed. More in our Cooling & noise glossary →Close ✕ tools, such as AMD’s Curve Optimizer or a voltage offset on Intel laptops, can cause it too, typically with crashes at idle or light load rather than in games.

How to check: think back: did the crashes start after changing BIOS settings, updating the BIOS (which can reset or change defaults), or applying a tuning profile?

Fix:

1. Enter the BIOS and load the defaults (Load Optimized Defaults; the keyboard key to press is shown at the bottom of the BIOS screen). This turns off XMP or EXPO too.
2. Use the PC normally for a few days. If the WHEA blue screens stop, an overclock or boost setting was the cause.
3. Turn on only XMP or EXPO again (cause 2), and leave automatic overclocking off, or use a milder setting. With Curve Optimizer, a smaller negative value (for example -10 instead of -30) is usually stable.

Our guide on how to clear CMOS shows how to reset the BIOS if you can’t get into it.

2. The memory profile (XMP or EXPO) is unstable

XMP or EXPO runs the RAM faster than its standard speed. On AMD processors in particular, the memory speed also sets the speed of the connection inside the processor, so an unstable memory profile can show up as a processor error.

How to check: turn XMP or EXPO off and use the PC for a few days. If the blue screens stop, the profile is the cause. A RAM test with XMP or EXPO on (how to test the RAM) can confirm it.

Fix:

• Update the BIOS first (cause 3): newer versions often make fast memory more stable.
• Choose a slightly lower memory speed than the profile, for example 5600 instead of 6000, and leave the other memory settings as the profile sets them.
• With four modules, expect to run a lower speed than with two.

Our guide on a PC that won’t start after enabling XMP explains these settings in detail.

3. The BIOS is out of date

BIOS updates include fixes from the processor maker that change how the processor manages its voltage and boost. Many WHEA problems are solved by a BIOS update alone.

This matters most for Intel Core 13th and 14th generation desktop processors (mainly Core i7 and i9, such as the i9-13900K or i7-14700K). Intel found that these processors could request too much voltage, which made some of them unstable over time. Intel released fixes as BIOS updates (microcode 0x12B in September 2024, then 0x12F in 2025) and extended the warranty on affected processors by two years.

How to check: type System Information in the Start menu. Note “BaseBoard Product” (your motherboard model) and “BIOS Version/Date”. Compare it with the newest BIOS on the maker’s support page for your exact motherboard.

Fix: install the newest BIOS, following the maker’s instructions exactly, then load the defaults. Install the chipset driver from the same page too. Our guide on how to find what caused a blue screen explains the update in more detail.

4. The processor has become unstable over time

If the BIOS is up to date, everything is at default, and the crashes continue or get more frequent, the processor itself may have become unstable. This is the known problem on some Intel 13th and 14th gen processors: a BIOS update prevents further damage, but it doesn’t repair a processor that’s already unstable.

How to check:

• WHEA errors keep naming “Processor Core” or “Cache Hierarchy” with everything at default.
• Games or apps crash while loading or decompressing files, often with “out of video memory” errors that make no sense.
• A tool like OCCT (free) shows errors in its processor test at default settings.

Fix: contact the processor’s maker or the shop. Intel has a warranty process for affected 13th and 14th gen processors, and both Intel and AMD replace processors that fail at default settings within warranty. As a temporary measure, limiting the processor’s maximum speed in the BIOS can make it usable until the replacement arrives.

5. The power supply can’t keep the voltage steady

The processor needs very steady power. An old, cheap or failing power supply can let the voltage dip under load, and the processor reports that as a hardware error.

How to check: the crashes come under load (gaming, rendering) and the power supply is old, budget, or was moved from a previous PC. Sudden switch-offs with no blue screen at other times strengthen the suspicion.

Fix: the surest test is a known-good power supply. Our guide on signs your PSU is failing explains how to test it safely, and how many watts you need helps you choose a replacement.

6. The processor is overheating

Processors slow themselves down when hot, but a cooler that has come loose or a pump that has failed can let temperatures spike fast enough to cause errors.

How to check: watch the processor temperature while you use the PC. Our guide on how to monitor temps while gaming shows how with free tools. Temperatures that hit the processor’s limit (often 95–100°C) within seconds of starting a game point to the cooler.

Fix: check the cooler is firmly mounted and its pump or fan works. Our guide on safe CPU temperatures while gaming explains what’s normal and how to bring them down.

7. Another part, such as the graphics card or an SSD, is reporting the error

WHEA errors don’t only come from the processor. A graphics card or NVMe SSD with a poor connection can report errors through the PCI Express connection.

How to check: Event Viewer names “PCI Express” or a “Root Port” as the error source (see how).

Fix:

• Reseat the graphics card and the NVMe SSD (PC off and unplugged).
• If the graphics card is mounted upright with an extension cable (riser), set the graphics slot to Gen 3 in the BIOS (often called “PCIe Link Speed”). Many extension cables aren’t reliable at faster speeds.
• Update the SSD’s firmware with its maker’s free app.

Real cases: what other users ran into

These are real threads from PC forums, summarized in our own words. Each one links to the original.

Real caseASUS ROG Strix G10CE · Core i7-11700F · RTX 3060SolvedBlue screens after closing games, solved by a BIOS updateRead what happened

From late October 2022, a prebuilt gaming PC kept crashing with WHEA_UNCORRECTABLE_ERROR, mostly right after closing a game. Memory and disk tests were clean, and changes to the CPU cooler didn’t help. A crash dump pointed to the motherboard maker’s control app, which was uninstalled and the BIOS reset to defaults. In the end, the person who posted reported that a BIOS update was what fixed it.

Takeaway: on prebuilt PCs especially, check the maker’s support page for a newer BIOS. See cause 3.

Source: Tom's Hardware Forum

Real caseRyzen 5 5600X · ASRock B550 Extreme4 · RX 6700 XT · Corsair GS600 (2009)SolvedAn old power supply caused WHEA blue screens in a modded gameRead what happened

In May 2023, after a year without problems, a PC started crashing with WHEA_UNCORRECTABLE_ERROR, mainly in a heavily modded Cities: Skylines with a browser open. Updating the chipset drivers, turning off PBO and reseating the RAM didn’t stop it, and memory and processor tests passed. Setting the RAM timings by hand instead of using XMP, plus a BIOS update, seemed to help at first. In October, the person who posted replaced the 14-year-old power supply, whose voltage readings had always looked normal, and reported that this fixed the issue.

Takeaway: an old power supply can cause WHEA errors even when its voltages look fine in software. See cause 5.

Source: TechPowerUp Forums

Real caseCore i9-13900KS · ASUS ROG Maximus Z790 Hero · 64 GB DDR5-6000Solved by replacing hardwareA 13th gen Intel processor that degraded after three monthsRead what happened

In December 2023, a PC that had run well for about three months started showing WHEA errors, blue screens and app crashes. Clearing CMOS, a BIOS update, memory tests on each module and several fresh Windows installs didn’t help. A test that loads one core at a time found errors on two specific cores. Lowering the processor’s speed reduced the crashes but didn’t stop them. The person who posted installed a new processor and reported the system completely stable, while the original went back under warranty.

Takeaway: if errors continue at default settings with the newest BIOS, the processor may need replacing. See cause 4.

Source: ASUS ROG Forum

Frequently asked questions

Does WHEA_UNCORRECTABLE_ERROR mean my processor is dead?

Usually not. Most cases are solved by loading the BIOS defaults, adjusting XMP or EXPO, or updating the BIOS. A faulty processor is only likely when the errors continue with everything at default and the newest BIOS installed.

Is it safe to keep using the PC?

Crashes can damage files that are being saved at that moment, so keep backups and fix the cause soon. The error itself doesn’t damage the hardware.

What are “corrected” WHEA errors?

Errors the hardware fixed on the spot, recorded in Event Viewer without a crash. A few after a BIOS change aren’t alarming, but many of them, or new ones every day, are an early sign of the same instability that causes the blue screen.

Can a graphics card cause WHEA_UNCORRECTABLE_ERROR?

Yes, although it’s less common. If Event Viewer names “PCI Express” as the source, check that the graphics card is pushed fully into its slot, and check the extension cable (if any) and the power cables (cause 7).

Does turning off XMP or EXPO make the PC slower?

A little, mostly in games on newer processors. It’s a test, not a permanent fix: once the cause is known, you can usually run the memory a step slower than the profile and keep most of the speed.