BSOD DRIVER_IRQL_NOT_LESS_OR_EQUAL — Blue Screen Driver Memory Access Error

Fix the DRIVER_IRQL_NOT_LESS_OR_EQUAL blue screen error caused by a driver attempting to access an invalid memory address at an elevated interrupt level. This guide covers everything you need to know about this topic, including common causes, step-by-step solutions, and answers to frequently asked questions.

Here are the key things to understand: Stop code DRIVER_IRQL_NOT_LESS_OR_EQUAL (0x000000D1) indicates a driver accessed invalid memory at a high IRQL. IRQL (Interrupt Request Level) is the priority level at which a driver's code runs in the kernel. Drivers at elevated IRQL can only access non-paged memory — accessing paged memory causes this BSOD. The BSOD message usually names the offending driver file (.sys) that caused the crash. This is one of the most common blue screen errors and is almost always caused by a faulty driver. Understanding these fundamentals will help you diagnose and resolve this issue more effectively.

The most common reasons this occurs include: Network adapter driver (commonly ndis.sys, tcpip.sys, or manufacturer drivers) accessing invalid memory. Recently installed or updated driver incompatible with the current Windows version. Faulty RAM causing memory access errors that trigger the IRQL check. Overclocked system causing memory instability at elevated interrupt levels. Identifying the root cause is the first step toward finding the right solution.

To resolve this, follow these recommended steps: Note the driver file name shown on the BSOD screen (e.g., ndis.sys, igdkmd64.sys). Boot into Safe Mode: hold Shift while clicking Restart > Troubleshoot > Startup Settings > Safe Mode. Update or roll back the identified driver: Device Manager > right-click device > Update driver or Roll Back. Run memory diagnostic: Win+R > mdsched.exe > Restart now and check for problems. If caused by overclocking, reset CPU and RAM to default clock speeds in BIOS. If these steps do not resolve the issue, consider consulting additional resources or a qualified professional.

This article is part of our Windows Error Codes collection on Error Codes Wiki. We provide comprehensive, up-to-date information to help you find solutions quickly.