Microsoft Security Essentials 4.5 for Windows 8.1

The new version of Microsoft Security Essentials for Windows 8/8.1 (x64 and x86) was released! It is compatible with Windows Vista, Windows 7 and unofficially Windows 8/8.1. The following tutorial shows you how to install it on Windows 8/8.1!

This is not an official updater! The MSE files have not been modified!
It supports Windows 8 RTM and 8.1 RTM, but may work with older versions too.
The author is not responsible for any damages this mod may cause to your system.

Microsoft Security Essentials for Vista / 7 = Windows Defender in Windows 8.1
Please DO NOT install MSE on Windows 8.1 because it is THE SAME program!
If you want, you can install it on Windows 8.1 – I REALLY DON’T CARE!

INSTALLATION / UPGRADE GUIDE (for Windows 8/8.1 only!)

Step 1 –  If Microsoft Security Essentials is installed in your Windows 8 system,
uninstall it by using my uninstaller (Steps 2-3) otherwise go to Step 5.

Step 2 – Open the “Control Panel” and navigate to “Programs and Features”.
Please check the version of MSE and use the correct Uninstaller program.

MSE Uninstaller for version 4.1.522.0 (x64)Download/Dropbox/OneDrive
MSE Uninstaller for version 4.1.522.0 (x86)Download/Dropbox/OneDrive
MSE Uninstaller for version (x64)Download/Dropbox/OneDrive
MSE Uninstaller for version (x86): It was not released!
MSE Uninstaller for version (x64)Download/Dropbox/OneDrive
MSE Uninstaller for version (x86)Download/Dropbox/OneDrive
MSE Uninstaller for version (x64)Download/Dropbox/OneDrive
MSE Uninstaller for version (x86)Download/Dropbox/OneDrive
MSE Uninstaller for version 4.4.304.0 (x64): Download/Dropbox/OneDrive
MSE Uninstaller for version 4.4.304.0 (x86): Download/Dropbox/OneDrive
MSE Uninstaller for version (x64)Download/Dropbox/OneDrive
MSE Uninstaller for version (x86)Download/Dropbox/OneDrive

Step 3 – You must log off and log in or restart your Windows to continue!

Step 4 – Download/unpack and double click on a “MSE_uninstall.reg” file.
MSE Uninstall (Registry Key): Download/Dropbox/OneDrive

Step 5 – Download the official MSE Beta Installer (x64 or x86):
Official MSE 4.0.1111.0 Beta (x64): Download/Dropbox/OneDrive
Official MSE 4.0.1111.0 Beta (x86): Download/Dropbox/OneDrive

Step 6 – Install MSE 4.0.1111.0 Beta (x64 or x86). Don’t forget to run this
program as an Administrator in compatibility mode for Windows 7!

Step 7 – Download and install the unofficial MSE Installer,
run this program as an Administrator.
MSE for Windows 8 (x64): Download/Dropbox/OneDrive
MSE for Windows 8 (x86): Download/Dropbox/OneDrive

Step 8 – You must log off and log in or restart your Windows to continue!

Step 9 – To prevent false detection of MSE in Windows Update List,
please download/unpack and double click on a “mse_4.4.304.0_register.reg” file.
MSE Register v4.5 (Registry Key): Download/Dropbox/OneDrive

Step 10 – Open Microsoft Security Essentials and update the virus definitions.
A further update (virus definitions) will be provided automatically by
Windows Update.

UNINSTALLATION GUIDE (for Windows 8 only!)

Microsoft Security Essentials (FE Mod) can’t be uninstalled in ordinary way, please download and run the unofficial uninstaller from First Ever.

Step 1 –  Follow the Steps 2-4 from the Installation/Upgrade Guide!

Step 2 – Open: “Control Panel” -> “Programs” -> “Programs and Features”

Step 3 – Uninstall “Microsoft Security Essentials”. After uninstalling MSE
you can use Windows Defenter.



Microsoft Security Essentials Modern Icon: Download/Dropbox/OneDrive

Microsoft Security Essentials Modern Icon

Please register on my website and if you have any questions, feel free to leave a comment!

Author: Marcin Grygiel aka Marcin-prv

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30 Responses to Microsoft Security Essentials 4.5 for Windows 8.1

  1. Christopher says:

    Have you found any issues with it?

  2. rkkdjb says:

    Hey Marcin, thanx btw, the links given in step 6 are interchanged i.e. the one given for x866 is actually for 64bit and vice versa plz correct thst.

  3. QuangDo says:

    Thank so much 😀

  4. Kaasknabbel says:

    when will it be available for windows 8.1?
    Tried to combine methods with compability etc. but nothing worked!

  5. usmangujjar says:

    thanks, this program works fine for me. please keep it up.

  6. Yopi says:

    Mr. Marcin, MSE 4.4.0304.0 release, please for Windows 8.1 RTM build 9600. Thank you

  7. usman gujjar says:

    your previous mse releases work fine for me… but mse 4.4 not working, it give error, and does not installed, it says some kind of: not valid batch file. and damaged windows files, also damged UAC.
    plase give me download link of your mse 4.3, this version worked good for me, but i accidently lost it.

  8. usman gujjar says:

    i do as you discribe, but after all when i checked, MSE 4.0.1111.0 is installed. i have used on win 8 x86 enterprise, pro & core. but my problem can’t fixed. please help me. THANKS in advance.

  9. Yopi says:

    Hello Mr. I can’t install MSE 4.4 in Windows 8 or Windows 8.1. Why?
    Thank you . .
    But, I Can install MSE 4.3 in Windows 8 or Windows 8.1.

  10. vasanthapriyan vasanthapriyan says:

    hai software intalling, but at the of install show as(windows did not pass genuine validation )
    ple give any solution

  11. Mauricio says:

    por favor,nao sei como baixar?/

  12. Fabio says:

    isn’t there the version 4.5 of MSE for Windows 8.1? Thank’s 😉

  13. Abdul Ahad Ali says:

    I’m using Windows 8.1 Pro (Update 1) X64 and I followed the steps above, fascinating, working 100% fine and normal.

    Thank you very much. 🙂

  14. akbar says:

    for windos 8 instal : clik right on the mseinstall-amd64fre-en-us.exe, properties, compatibility, chacklist ” Run This Program as an administrator” , and checklist ” Run this program in comatibility mode for”: (Windows 7). click ok,and finish , doubel click mseinstall-amd64fre-en-us.exe and anjoy..

  15. Janardan K Mhatre says:

    How to Install Microsoft Security Essentials in Windows 8.1

  16. sudheer says:

    MSE Uninstaller for version (x64): Download/Dropbox/OneDrive is not found. please check the link

  17. roirraWedorehT says:

    Hi Marcin! Thanks again for your work. I’m fed up with Windows and switched to Ubuntu, but I must have Directory Opus by GPSoftware, so I’m running XP x64 in VMWare Workstation in Ubuntu, and I wanted to see if your hacked Microsoft Security Essentials x64 would work with it. It seems totally fine!

    I still have to upgrade it to 4.5, which I will when this scan is over.

  18. roirraWedorehT says:

    Hmmmm, it appears that 4.5 makes it realize it’s running on an end-of support Windows installation, so I’ve reverted back to my snapshot of before upgrading to 4.5 and it seems fine. Guess I’ll just keep it there.

  19. roirraWedorehT says:

    Apparently I was able to use Microsoft Update to upgrade MSE on XP x64 from 4.0 to 4.1 and then another session to go from 4.1 to 4.4, and 4.4 works okay – makes sense since 4.5 was after end of support for XP. I’m sure I could’ve used your 4.4 zip to upgrade it instead, and I’ll keep that handy just in case. 🙂 Sorry for SPAMing your board.

  20. Mansoor says:

    Hello Mr Marcin!
    i have downloaded the MSE but it does not run in windows 8.1.1 please show me the way for such a problum
    thank you!

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