KMODE_EXCEPTION_NOT_HANDLED, the blue screen, explained and fixed

This stop code (0x0000001E) means a program running in kernel mode, the most privileged part of Windows, generated an exception that the error handler could not catch. In practice it is a near relative of SYSTEM_THREAD_EXCEPTION_NOT_HANDLED: buggy drivers first, faulty RAM second, and the blue screen frequently names the driver file involved.

The fix, in order

  1. Check for a driver file name on the blue screen. If a .sys file is listed, that driver is the starting point: update it from the device maker’s site, or roll it back in Device Manager if the crashes began right after it updated.
  2. Boot into Safe Mode and remove recent additions. Hold Shift while choosing Restart → Troubleshoot → Advanced options → Startup Settings → Safe Mode. Uninstall any driver, antivirus, or system utility installed just before the crashes started.
  3. Update the main driver set. Graphics, chipset, network, and storage drivers from the PC or motherboard manufacturer. Avoid third-party driver-updater tools, they install mismatched drivers that cause exactly this crash.
  4. Repair system files. Admin Command Prompt: DISM /Online /Cleanup-Image /RestoreHealth, then sfc /scannow.
  5. Run a memory test. Windows Memory Diagnostic, and for a stronger check let it run several passes overnight. Kernel-mode exceptions with no pattern are a classic bad-RAM symptom.
  6. Remove any overclock. Return CPU and RAM to stock speeds in the BIOS/UEFI setup, including disabling XMP if the crashes are new, then test again.

If it still happens

If the code appears during boot before you can sign in, use the recovery menu (it appears after two failed boots) for Safe Mode, Startup Repair, and System Restore. If it persists after clean drivers, repaired files, and passing memory tests, check drive health with chkdsk /f. A crash that survives a clean install is pointing at hardware, most often RAM, then the drive, then the motherboard.

Common questions

What is the difference between KMODE_EXCEPTION_NOT_HANDLED and SYSTEM_THREAD_EXCEPTION_NOT_HANDLED? Both mean an unhandled exception in kernel code. 0x1E is raised when a kernel-mode program causes the exception, 0x7E when a system thread does. The troubleshooting is nearly identical, drivers first, memory second, because the same faults produce both.

My antivirus was named on the screen. Should I remove it? Security software runs deep in the kernel and is a frequent source of this crash when it corrupts or goes out of date. Update it first; if the crashes continue, uninstall it temporarily (Windows Security keeps the PC protected in the meantime) and see whether the crashes stop.

Related errors

SYSTEM_THREAD_EXCEPTION_NOT_HANDLED · MEMORY_MANAGEMENT · PAGE_FAULT_IN_NONPAGED_AREA · CRITICAL_PROCESS_DIED