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DRIVER_IRQL_NOT_LESS_OR_EQUAL

DRIVER_IRQL_NOT_LESS_OR_EQUAL (0xD1) on Windows: a driver failed

Verified with sources3 sourcesReviewed Oct 4, 2026
Technician coming? See the 3 steps they must show you

Risk level

Medium

Proceed carefully and stop if the check is unclear.

Urgency

High

Quick answer

Windows stopped because a driver accessed memory it was not allowed to use at that moment. See whether the blue screen names a .sys file and update or uninstall that driver from its maker's website.

Safety first

Stop and check this first

  • A driver name on screen does not mean the device is broken: 0xD1 mostly points to driver software. Do not replace parts without a diagnosis that justifies it.

Safe checks you can perform

  • .sys file on screen and in the log
  • Undo the last driver or device
  • Safe Mode and updates

Leave these tasks to a qualified professional

  • Do not attempt this professional task: Identify the driver in the dump
  • Do not attempt this professional task: Test with Driver Verifier
  • Do not attempt this professional task: The device maker

What a technician must be able to justify

Technician visit

These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.

These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.

  1. Identify the driver in the dump

    What they doThe technician opens the dump in WinDbg, runs !analyze -v and dx KiBugCheckDriver, and uses ln on parameter 4 to see which function accessed the memory.

    They must show youthe output with the driver name.

    In writingwhich driver it was, its version and what was done with it.

  2. Test with Driver Verifier

    What they doIf the dump is not enough, they set up Driver Verifier (verifier) on as few suspect drivers as possible and reproduce the failure.

    They must show youwhich drivers were tested and the result.

    In writingthat Driver Verifier was turned off afterwards and the conclusion.

  3. The device maker

    What they doWith the driver identified, the device maker is asked for a fixed version or confirmation of compatibility.

    They must show youthe version the maker recommends.

    In writingthe case number or reference of the fixed driver.

Before accepting a part or repair

Nothing has been shown yet. Do not accept a part swap based on the code alone.

Follow these steps

Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.

  1. .sys file on screen and in the log

    No special tools

    Who:
    you.
    How:
    take a photo of the blue screen and see whether it names a file ending in .sys; then check Event Viewer, Windows Logs, System, at that time.
    Result that matters:
    whether a specific driver is identified.
    If one appears:
    look for an updated version on its maker's site or uninstall it.
    If none appears:
    go on to recent changes.
    Evidence to keep:
    photo of the screen and screenshot of the event.

    Evidence: Troubleshooting Windows unexpected restarts and stop code errors · Bug Check 0xD1 DRIVER_IRQL_NOT_LESS_OR_EQUAL

  2. Undo the last driver or device

    No special tools

    Who:
    you.
    How:
    if you installed a device or updated a driver before the first crash, open its properties in Device Manager and use Roll Back Driver, or unplug the device if it comes out without tools.
    Result that matters:
    whether crashes stop after going back.
    If they stop:
    the new driver version was the cause; tell the maker.
    If they continue:
    the change does not explain it.
    Evidence to keep:
    name and version of the rolled-back driver.

    Evidence: Stop code error or bug check troubleshooting (IT professionals) · Troubleshooting Windows unexpected restarts and stop code errors

  3. Safe Mode and updates

    No special tools

    Who:
    you.
    How:
    if you cannot reach the desktop, start in Safe Mode; from there install Windows Update updates and check you have at least 10% to 15% free space.
    Result that matters:
    whether the system stays stable after updating.
    If it stays stable:
    an update fixed the driver.
    If 0xD1 returns:
    the case goes to a technician with the dump.
    Evidence to keep:
    list of updates installed and free space.

    Evidence: Troubleshooting Windows unexpected restarts and stop code errors

Still not solved

If the error persists, stop here. See what the technician must do and show you.

Where this code applies

A code is meaningful only inside the right product and version context.

Primary scope

System
Software and digital services
Brand
Microsoft Windows
Product type
Operating system

Known code variants

  • 0x000000D1
  • 0xD1
  • DRIVER IRQL NOT LESS OR EQUAL
  • STOP 0x000000D1
  • stop code DRIVER_IRQL_NOT_LESS_OR_EQUAL

What it means

Microsoft defines bug check 0x000000D1 as a kernel-mode driver that tried to access pageable memory (or an invalid address) while the interrupt request level (IRQL) was too high. It says the usual cause is drivers using improper memory addresses: a bad pointer, a function in another driver that was already unloaded, or pageable code run at that level. If the driver is identified, its name is shown on the blue screen. The code points to driver software and does not prove a part is broken.

Warnings and stop conditions

  • Mediumeditorial warning

    A driver name on screen does not mean the device is broken: 0xD1 mostly points to driver software. Do not replace parts without a diagnosis that justifies it.

    Evidence: Bug Check 0xD1 DRIVER_IRQL_NOT_LESS_OR_EQUAL

Symptoms and causes

Probable causes · in order

  • Driver using improper memory addressesCommon

    Microsoft gives it as the usual cause; you can tell because the blue screen or dump names a specific .sys file.

    Evidence: Bug Check 0xD1 DRIVER_IRQL_NOT_LESS_OR_EQUAL

  • Hardware driver just installed or updatedPossible

    Suspected if the crashes began after installing a device or updating its driver.

    Evidence: Troubleshooting Windows unexpected restarts and stop code errors · Bug Check 0xD1 DRIVER_IRQL_NOT_LESS_OR_EQUAL

  • New hardware not compatible with your WindowsPossible

    Microsoft asks you to confirm that installed hardware is compatible with your Windows version.

    Evidence: Bug Check 0xD1 DRIVER_IRQL_NOT_LESS_OR_EQUAL

Virtual technician

Does DRIVER_IRQL_NOT_LESS_OR_EQUAL still appear after these checks?

Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.

Start diagnosis

Sources and technical references

  1. 1

    Stop code error or bug check troubleshooting (IT professionals)

    Microsoft · 2026 · official_doc

  2. 2

    Troubleshooting Windows unexpected restarts and stop code errors

    Microsoft · 2026 · official_doc

  3. 3

    Bug Check 0xD1 DRIVER_IRQL_NOT_LESS_OR_EQUAL

    Microsoft · 2026 · official_doc

Sources: Stop code error or bug check troubleshooting (IT professionals) · Troubleshooting Windows unexpected restarts and stop code errors · Bug Check 0xD1 DRIVER_IRQL_NOT_LESS_OR_EQUALreviewed 2026-10-04 · verified

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