Windows BSOD Error 0x00000056 — INSTRUCTION_COHERENCY_EXCEPTION Fix

What Does This Error Mean?

The 0x00000056 blue screen means Windows detected an instruction cache coherency problem. This is called INSTRUCTION_COHERENCY_EXCEPTION. It usually points to a CPU hardware fault, overclocked processor instability, or a driver that is issuing illegal processor instructions. This error is less common than most BSODs and almost always requires hardware investigation.

Affected Models

Windows 10
Windows 11
Windows Server 2016
Windows Server 2019

Common Causes

The CPU is overclocked beyond a stable frequency, causing it to produce incorrect instruction results
A defective or failing CPU has developed hardware faults in its instruction cache or execution units
A device driver is executing processor instructions that violate processor architecture rules
RAM running at an unstable XMP or overclock profile is feeding bad data to the processor
Thermal throttling from a failing CPU cooler is causing the processor to operate erratically

How to Fix It

Disable any CPU or RAM overclocking immediately. Restart your PC, enter BIOS (usually by pressing Delete or F2 at startup), and reset all settings to default or 'optimized defaults.'

This is the most important first step. An unstable overclock is the leading cause of instruction coherency errors. Even a slight overclock that seemed stable before can cause this error under specific workloads.
Update or roll back your device drivers. Open Device Manager (right-click Start > Device Manager), look for any devices with a yellow warning icon, and update those drivers first.

A recently installed or updated driver that issues bad processor instructions can trigger this BSOD. Rolling back the driver to the previous version is sometimes faster than finding a new update.
Run the Windows Memory Diagnostic tool. Press Windows key + R, type mdsched.exe, and press Enter. Choose 'Restart now and check for problems.'

Even if RAM is not overclocked, faulty memory can send corrupted data to the processor. The memory diagnostic runs a thorough test during the restart and reports results when Windows loads again.
Check your CPU temperature. Download a free tool like HWMonitor or Core Temp and watch the CPU temperature while the computer is under load. Normal temperatures should stay below 90°C.

A CPU running too hot because of a failing cooler or dried-out thermal paste will throttle and behave erratically. If temperatures spike over 90°C, reapply thermal paste and clean the cooler.
Run System File Checker to rule out corrupted Windows files. Open Command Prompt as Administrator and type: sfc /scannow — let it finish, then restart.

Although this error is primarily hardware-related, corrupted Windows system files can sometimes cause driver issues that trigger unusual BSODs.

When to Call a Professional

If disabling overclocking does not resolve this error, the CPU itself may be failing. A hardware technician can run CPU stress tests to confirm whether the processor is defective. CPU replacement is not a beginner task — it requires removing the cooler, reapplying thermal paste, and seating the new chip correctly. If your PC is under warranty, contact the manufacturer before attempting any hardware changes.

Frequently Asked Questions

What is instruction cache coherency and why does it cause a crash?

Your CPU has a small, ultra-fast memory cache that stores instruction code it expects to need next. Instruction cache coherency means all parts of the CPU are working from the same, correct version of those instructions. When coherency breaks down — due to a hardware fault or bad driver — the CPU may execute the wrong instructions. Windows detects this and immediately crashes to prevent data corruption or worse system damage.

Can this error be caused by a virus?

It is rare, but certain rootkit-level malware can interfere with processor-level operations. Run a full scan with Windows Security (or Malwarebytes) to rule out malware before assuming hardware failure. However, in the vast majority of cases, 0x00000056 is caused by overclocking, driver faults, or failing hardware — not malware.

If my CPU is failing, does the whole motherboard need replacing too?

Not necessarily — the CPU and motherboard are separate components. However, CPU sockets are unique to each motherboard generation. If you replace a CPU with a different model or generation, it may not be compatible with your existing motherboard. A technician can advise you on compatible replacement options for your specific system.