How to Fix IRQL_NOT_LESS_OR_EQUAL Error in Windows 8.1✅

IRQL_NOT_LESS_OR_EQUAL error is a typical BSOD error in systems and it happens more frequently when Windows users try to update their systems into a new version. 
Here below, you'll see effective methods to fix this irql_not_less_or_equal error due to system update or memory crashes. 

Causes for IRQL_NOT_LESS_OR_EQUAL Error 

Knowing reasons for irql_not_less_or-equal error will be very helpful for us to prevent and find relative solutions for this problem. Here below are some major reasons for this problem:

• Incompatible device drivers
• Poor device driver installation
• Faulty hardware
• Disk fragmentation
• Registry issues
• Viruses and malware attack

What problems will the irql_not_less_or_equal error cause to your computer? The most serious problems should be system crash, system failure and even data loss etc. So how to avoid such a problem and how to find solutions to fix it? 

Bonus Tip: Backup system and data regularly to avoid irql_not_less_or_equal error

In order to avoid unexpected system failure, crash or data loss trouble when an irql_not_less_or_equal error occurs, it's highly recommended for you to create a system backup image and backup important Windows data in advance.

If necessary, a WinPE bootable disk is also highly recommended. How to do all these things? EASY! Here we recommend you to try professional Windows backup software - EaseUS Todo Backup which allows you to free back up and restore system, data and even hard drive partition within 30 days. You can free download it here and start backup Windows data and system now.

Solutions to fix irql_not_less_or_equal error in Windows 8.1

Since irql_not_less_or_equal error occurs frequently on many Windows systems such as Windows 10/8 etc, here below you'll find 5 methods to fix this problem and get your computer out of BSOD problem.

Method 1. Repair Registry and Fragmented Disk

1. Press "F8" to enter the Safe Mode and select "Repair My Computer" > Enter Command Prompt in "Advanced Options" under "Troubleshoot".
2. Select "Command Prompt" and type below commands to find the root directory:

dir C:\Win* and hit Enter.
dir D:\Win* and hit Enter.
dir E:\Win* and hit Enter.

3. Type: 
cd /d C:\windows\System32\config + hit Enter.
xcopy *.* C:\RegBack\ + hit Enter.
cd RegBack + hit Enter.
dir + hit Enter;

4. Type below commands:
copy /y software ..
copy /y system ..
copy /y sam ..
And finally, click yes to finish the commands. Then reboot the computer, the registry will be manually fixed and repaired.

Method 2. Roll Back Drivers

1. Go to the Control Panel > Double click the system icon and locate the "System Properties".
2. Click hardware tab > click "Device Manager" > locate the device you recently installed and double click it;
3. Click the driver tab and the rollback driver button.

Method 3. Run Hardware Diagnostic

1. Type: Memory Diagnostic in the search and enter this tool.
2. Click "Diagnostic" your memory problems and it will ask you to perform the check by restarting PC immediately or on the next restart.
3. Scan on the memory and it will show a list of problematic errors detected during the scan.
4. Replace all faulty hardware detected in the scan and reboot PC.

Method 4. Disable Memory Caching

Press "F2" or other keys > Enter the BIOS > Disable "Memory caching feature".

Method 5. Scan and remove Malware in PC

To perform this method, you need to use some anti-virus software to scan and thoroughly remove all Malware from your PC and then reboot the computer. The unwanted irql_not_less_or_equal problem will be fixed.