Hardware and CPU errors

UNEXPECTED_KERNEL_MODE_TRAP (0x0000007F)

Stop code 0x0000007F, also written 0x7F. Here is what it means, what usually causes it, and the safest order to work through fixes on Windows 11 and Windows 10.

In short

The processor raised a fault the kernel could not handle, often tied to memory, heat or overclocking.

What UNEXPECTED_KERNEL_MODE_TRAP means

The processor generated a trap, a type of fault, that the kernel is not allowed to handle. Hardware causes such as faulty RAM, overheating and unstable overclocks are common, although software and drivers can trigger it too.

Common causes

Faulty RAM or memory settings that are not stable
Overheating or an unstable CPU overclock
A faulty driver or incompatible software
Failing motherboard or CPU hardware

How to fix UNEXPECTED_KERNEL_MODE_TRAP

Work through these in order and test after each one. Stopping as soon as the crashes stop tells you which change mattered.

Test the memory. Run Windows Memory Diagnostic (search for it in Start) for a quick check, then MemTest86 for several passes if the crashes continue. Any error points to a faulty stick or slot, or to memory settings the hardware cannot run reliably.
Return the PC to stock settings. Reset the BIOS to defaults, then leave XMP or EXPO, CPU or GPU overclocks and undervolts (including per-core offsets such as Curve Optimizer) switched off while you test. If the crashes stop, re-enable one setting at a time to find the unstable one.
Watch temperatures under load. Use a monitoring tool to log CPU, GPU and drive temperatures while you reproduce the problem. Sustained high readings, loud fans or thermal throttling point to dust, failed fans or poor airflow rather than a software fault.
Undo the most recent change. If the blue screens began after a Windows update, a new driver or new software, remove that change first. Uninstall the update from Settings, Windows Update, Update history, or roll a driver back in Device Manager (right-click the device, Properties, Driver, Roll Back Driver).
Repair Windows system files. Open Terminal (Admin) and run sfc /scannow. If it reports damage it could not repair, run DISM /Online /Cleanup-Image /RestoreHealth, restart, and run sfc /scannow once more.

When to stop and protect your data

Crashes that continue at stock settings with passing memory tests justify testing other hardware, starting with the power supply and the motherboard.

Not sure this is your code?

The stop code appears as text on the blue screen. If the PC restarted before you could read it, open Event Viewer, then Windows Logs, then System, and look for a BugCheck event with ID 1001. You can also search all stop codes.

Related guides

Other hardware and cpu errors

WHEA_UNCORRECTABLE_ERROR (0x124)
CLOCK_WATCHDOG_TIMEOUT (0x101)

Frequently asked questions

What does UNEXPECTED_KERNEL_MODE_TRAP mean?

The processor raised a fault the kernel could not handle, often tied to memory, heat or overclocking. The processor generated a trap, a type of fault, that the kernel is not allowed to handle. Hardware causes such as faulty RAM, overheating and unstable overclocks are common, although software and drivers can trigger it too.

What usually causes UNEXPECTED_KERNEL_MODE_TRAP?

Typical causes: Faulty RAM or memory settings that are not stable; Overheating or an unstable CPU overclock; A faulty driver or incompatible software; Failing motherboard or CPU hardware.

How do I fix UNEXPECTED_KERNEL_MODE_TRAP (0x0000007F)?

A sensible order is: 1) Test the memory; 2) Return the PC to stock settings; 3) Watch temperatures under load; 4) Undo the most recent change. Crashes that continue at stock settings with passing memory tests justify testing other hardware, starting with the power supply and the motherboard.

Use this guidance carefully

A stop code can have several causes, and these steps are general guidance rather than a diagnosis of your PC. If your data matters, back it up before repairs. If the problem continues, a hardware technician can test the parts.

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