Good Day/Night folks,

This morning i have updgraded windows 8.1 to windows 10, I found so many good things,

except when I tried changing my computer name from "Acer" to "Cerena", It asked me to

restar so I did, then when it started booting up, i have this irql_not_less_or_equal mfewfpk.sys

bluescreen error, i thought it was nothing so i just waited, but it kept coming back, so i booted

to safe mode, unfortunately i can't do ****, anyway, i tried rebooting then here I am asking some 

answers for this problem, I located the file in the system32 driver folder and noticed there are more 

"mf" system files, i decided to cut and paste them in my documents folder. 

can someone please help,

UPDATE" AUGUST 25 2015 2136H GMT+8

Hi guys, thank you for all your replies,

as you can see, I tried everything, like boot in safe mode, clean boot and stuff,

but it kept on, so I tried removing the file in my system, just as sir Boston did,

I didn't have that same error since, maybe try that solution as well,

thank you guys again for being helpful.

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Thank you for your interest in Windows 10.  I will certainly help you with this issue.

Mfewfpk.sys is a type of SYS file associated with McAfee Total Protection. This issue could cause if the McAfee.

I would suggest you the following methods.

Method 1: Windows 10 has Windows Defender as security software however if you wish to run MaAfee you can check the compatibility by running compatibility troubleshooter.

  • Press Windows key on the keyboard.
  • Type troubleshooting.
  • Run the Program Compatibility Troubleshooter.

This will let you know if the program is compatible or not.

Method 2: Check in safe mode and clean boot mode of the computer

Step 1: Check in Safe mode

Safe mode is a troubleshooting option for Windows that starts your computer in a limited state. Only the basic files and drivers necessary to run Windows are started. The words Safe Mode appear in the corners of your monitor to identify which Windows mode you're using.

Refer the link below:

Start your computer in safe mode

Refer to Windows 8.1 steps, as they are applicable to Windows 10.

You can restart the computer to put it back in normal mode.

If the issue doesn’t occur in safe mode, follow step 2.

Step 2: Perform Clean Boot

Placing your system in Clean Boot state helps in identifying if any third party applications or startup items are causing the issue. You need to follow the steps from the article mentioned below to perform a Clean Boot.

How to perform a “clean boot” in Windows  

Refer to Windows 8.1 steps, as they are applicable to Windows 10.

Note: Refer "How to reset the computer to start normally after clean boot troubleshooting" to reset the computer to start as normal after troubleshooting.

If the issue still persists, follow method 3.

Method 3: Remove McAfee

Uninstall and reinstall with McAfee with Windows 10 

McAfee removal -

Note: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.

Let us know if you need further assistance. We will be glad to help you further.


Thanks & Regards,

Isha Soni

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I have the same issue after upgrading to Windows 10 yesterday. I keep getting this error irql_not_less_or_equal mfewfpk.sys. I have tried all the methods mentioned but still got the same problem. Currently still troubleshooting on my own. Tried to perform system restore as well but that didn't work either. Hope somebody can help us on this problem. 

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Sorry this didn't help.

I had to remove the offending McAfee file manually, then Windows 10 restarted OK.  The Windows 10 installation says it is uninstalling McAfee, but it apparently doesn't do a complete job.

When the Troubleshooting option appears, click it and choose Command Prompt.   The prompt will come up as X:\ but you don't want that.  Type cd C: to change directory to the C: drive.  Then type cd \windows\system32\drivers (& push Enter) to get to the C:\windows\system32\drivers directory.  To check that the offending mfewfpk.sys file is there, type dir /p (& push Enter), and keep moving down the list using spacebar until you get to the beginning of the "m" list of files.  I had six files starting with "mfe".  I thought about deleting all six, but deleted only mfewfpk.sys and that did the trick.  While still at the C:\windows\system32\drivers directory, type del mfewfpk.sys (& push Enter) and you'll get a response that the file was deleted.  (If it says file not found, check your spelling!)  Then type exit (& push Enter).  Choose "Turn computer off".  Upon restart, my Windows 10 was fine.  (But haven't restarted again, so hope it is permanently OK; if not, I'll delete the other mfe*.sys files.)

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19 people were helped by this reply

I do not have Mcaffee installed, never have, nor will I. My opinion, but I think it is a terrible program, so anyway, I do have "Norton Endpoint Protection" in use.

Where would the Mcaffee file, or program even have came from? I know it is often an option to "download free trial" in several sites, but I always "uncheck" the box so as not to install.

I will try these methods and see what I find. It happened shortly after the upgrade, and when the OS did a "critical update" later that evening............
I suppose, for now, I will change update settings to show me what I'm installing first, as I had to before, as I am wondering if Mcaffee may have been a part of this update?

I've had updates in win 8.1 pro install, and disable things, most recently it installed a jacked up graphics driver.

Easy fix, just a pain to find out what was causing the problem.

Will update further.

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McAfee is offered free by my employer, even for personal computers.  It was already on my computer for a long time prior to updating to Win 10.  I haven't found Win 10 to add unwanted stuff from third parties.

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That may be the case, however, I still would lik eto know how anything regarding McAfee of any sort, got there in the first place.

I build all my systems, Load specific programs following the OS in a certain order as I learned over the years, and never open one until all are loaded and a boot defrag is done. 15 years, never had an issue other than a bogus GFX driver about 3 months ago, nor anything McAfee on any system after a bad experience as a result of a coop issue between Them and AOL. As well, I've not used anything involving AOL since then either.

At this point, I can't restore. I can't get system to open in safe mode, it keeps going back to the "system did not start properly" screen.

Will try a couple options, but may have to uninstall and start over, making sure the file isn't there before the upgrade.

Otherwise, was working fine, until it's first "critical update" This is the odd part to me.

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Ok, further investigation, I have 2 systems. The one which updated to Win 10, had the McAfee .sys file, I deleted, waiting to see if it restarts.

The system I use most often for my business is still on Win 8.1 pro, doind the same system dir search, there is no mfewfpk.sys file.

It is now my opinion, it was installed when the Win 10 upgrade was done, or as part of the "critical update".

There IS NO other explanation............

No third party softwares? Going to have to agree to disagree for now.

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We do need the actual log files (called a DMP files) as they contain the only record of the sequence of events leading up to the crash, what drivers were loaded, and what was responsible.  

Please follow our instructions for finding and uploading the files we need to help you fix your computer. They can be found here
If you have any questions about the procedure please ask

Cat herder
Windows Insider MVP
MVP-Windows and Devices for IT

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Sorry this didn't help.

Deleted file through CMD, is working now, but is restored to a point before update.

Will change update setting immediately.

Have one more issue if anyone can help.

On my one PC, I've never received the 10 upgrade invitation. It said I needed updates.

I have ran windows update, a couple times, says "no updates available at this time".

I am using a retail purchased version of 8.1 pro

Any ideas? or should I just get the installer pack and do it on my own?


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hi, I have another irql bluescreen error, i have a dmp file here

please help.

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Views: 11,022 Last updated: May 27, 2018 Applies to: