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FIX: Driver irql not less or equal (mfewfpk.sys) error
7 min. read
Updated onMarch 19, 2024
updated onMarch 19, 2024
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Key notes
As you know,Windows 10is available as a free upgrade to all genuine Windows 8 and Windows 7 users.
However, the upgrade process to Windows 10 isn’t always smooth and some users report getting driver_irql_not_less_or_equal (mfewfpk.sys) error.
Driver_irql_not_less_or_equal (mfewfpk.sys) is usually followed by aBlue Screen of Deathafter which your computer restarts.
This error is caused by a file mfewfpk.sys that is related toMcAfeeSecurity Software, and usually, the best solution to this is to removeMcAfeesecurity software before upgrading to Windows 10.
If you have already upgraded to Windows 10, don’t worry, there’s still a way to fix this issue.
How do I fix Driver_irql_not_less_or_equal (mfewfpk.sys) error?
1. Start Windows 10 in Safe Mode
If the problem is resolved after removingMcAfee, you might want to keep usingWindows Defenderor switch to a different antivirus solution.
Windows Defender offers solid protection, but if you want full system protection, it might be wise to installthird-party antivirus software.
2. Move the problematic file to a different directory
After doing that, restart your PC and the problem should be completely resolved. Keep in mind that this isn’t a system file, so you can also remove it if you want.
In most cases, this problem is caused by mfewfpk.sys, and in order to fix this issue, you need to find and move the file to a different location.
This file is located in the Windows directory, but it’s not crucial for Windows, so you can easily move it.
3. Perform a System Restore
After performing a System Restore, your PC should be restored to an earlier state, and the problem should be resolved completely.
Keep in mind that this isn’t a perfect solution, and sometimes even the System Restore won’t be able to fix your problem.
Use a third-party system restoration tool
You can also restore your system files using athird-party specialized tool, so you won’t need to use any System Restore and lose your current windows files and settings.
Simply download the tool, run it, and it will automatically scan the system for corrupted, damaged, or missing files, and then it will restore them or replace them accordingly.
4. Use Linux boot drive
If driver_irql_not_less_or_equal (mfewfpk.sys) error is preventing you from starting Windows, you might be able to fix the problem simply by booting from a Linux boot drive.
Keep in mind that in a Linux environment your drive might not be labeled as C, so you’ll have to find the Windows directory on your own.
This is a bit advanced solution, so if you don’t know what is an ISO file or Linux, and if you don’t know how to create a bootable drive, you might want to read a tutorial or two or try a different solution.
5. Remove McAfee
Since McAfee is supposedly a cause of this error, removing the program is the safest solution. You can do it from within the device manager, or you can use a third-party app removal tool.
To do this, you will need to download and run aMcAfeeremoval tool. After you’ve downloaded the tool, you just need to run it and it will removeMcAfeeSecurity Software completely from your computer.
If you’re getting Blue Screen of Death with driver_irql_not_less_or_equal (mfewfpk.sys) error then you probably won’t be able to access your system.
To download the necessaryMcAfeeremoval tool, you’ll have to start your Windows 10 in Safe Mode.
⇒Get IObit Uninstaller
6. Use Command Prompt to remove the file
This command will force Windows to remove this file. After doing that, just restart your PC and check if the problem is resolved.
7. Use Windows 10 installation media to perform Automatic Repair
If you aren’t sure how to do it, know that you can learn how to boot from a USB drive with ouruseful article. Just follow the steps and you’ll know how to do it in no time.
Note: Before you start, you need to download Windows 10 ISO using theMedia Creation Tooland create a bootable drive. You can do that from Safe Mode or from a working PC.
A variation of this error can appear on any Windows operating system, and we wrote about theIrql Not Less or Equal error in Windows 11in another guide, so don’t miss it.
We hope these solutions helped you with Driver_irql_not_less_or_equal (mfewfpk.sys) error, if you have any questions, or comments, just reach for the comment section below.
More about the topics:BSoD error codes,System Files
Ivan Jenic
Windows Hardware Expert
Passionate about all elements related to Windows and combined with his innate curiosity, Ivan has delved deep into understanding this operating system, with a specialization in drivers and driver troubleshooting.
When he’s not tackling diverse driver-related problems, Ivan enjoys watching good movies and spending time hiking with his family and friends.
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Ivan Jenic
Windows Hardware Expert
Ivan has delved deep into understanding the Windows OS, with a specialization in drivers and driver troubleshooting.
