Windows Malicious Software Removal Tool

Microsoft has released a Windows “Update” that is designed to remove software from your computer:

After the download, this tool runs once to check your computer for infection by specific, prevalent malicious software (including Blaster, Sasser, and Mydoom) and helps to remove any infection found. If an infection is found, the tool will display a status report the next time you start your computer. A new version of the tool will be offered every month. If you want to manually run the tool on your computer, you can download a copy from the Microsoft Download Center or run an online version from microsoft.com. This tool is not a replacement for an anti-virus product. To help protect your computer, you should use an anti-virus product.

I see their intent behind this, but I still find it disturbing. Although some users don’t know how to determine what software is on their computer, I have no need for this tool. And yet it was still downloaded automatically and is considered a Critical “Update.”

Sept 16, 2005 Update Looks like Microsoft has created a new version of this tool.

Size: 400 KB

After the download, this tool runs once to check your computer for infection by specific, prevalent malicious software (including Blaster, Sasser, and Mydoom) and helps to remove any infection found. If an infection is found, the tool will display a status report the next time you start your computer. A new version of the tool will be offered every month. If you want to manually run the tool on your computer, you can download a copy from the Microsoft Download Center or run an online version from microsoft.com. This tool is not a replacement for an anti-virus product. To help protect your computer, you should use an anti-virus product.

More information for this update can be found at http://www.microsoft.com/malwareremove

26 Responses to “Windows Malicious Software Removal Tool”

  1. Barbara Colin says:

    This update has caused me so many problems that I used system restore and went back to before the install!!! I create a restore point prior to doing ANY updates! Good thing I follow this habit!!! After the update install, my computer ran VERY, very slow. I couldn’t use my start button to open my programs list very well. It took forever to open, if at all on first try, and then the flyouts wouldn’t open very quickly either!!! I couldn’t get my task manager to open from the taskbar either! All shortcuts to my browsers wouldn’t work! What a ridiculous update and I agree with you totally!! Critical? Yea, right!!!

  2. Anonymous says:

    It messed up my anti-virus software badly. I can’t update and re-install it!

  3. Anonymous says:

    Shame on Microsoft – again.

  4. Anonymous says:

    I use FireFox and and this update removed all my browser’s extentions, Had to restore my computer to before the update.

  5. Other Anonymos says:

    I can’t install this update on my XP. If I let the install, after the reboot the computer say me the new update is available (this again). Why?

  6. Elgin says:

    I fear I have become a victim of this rediculous update. After the update I get the infamous “Blue Screen of Death” referring to a KMODE_EXCEPTION_NOT_HANDLED. And worse yet, the error gives no indication as to the module that is affected. I read at Microsoft that there is no uninstall. AHHH! I’m on Windows 2000 and do not have a restore point.

  7. Anon says:

    It’s all in the title:
    “Windows Malicious Software”

  8. Gautam Naidu says:

    Hi,

    Please give me clear instruction as to how can I
    UNINSTALL the KB890830: Microsoft Malicious Software Removal Tool.

    Because I have understood by various techniques that this update freezes the PC from playing many games.

    Regrads,
    Gautam Naidu.

  9. Matthew says:

    So, what do we do to fix this if we didn’t save a Restore Point before trying to install this update?

  10. Milo Aloysius says:

    I just called Microsoft, they want $35.00 to tell me how to uninstall this “malicious” program from my home machine and $200.00 to tell me how to uninstall it from a corporate network. Yikes!!!

  11. thor says:

    After I ran this update my MCE2005 computer had a BSOD on every boot. I had to restore in safe-mode to a previous restore point. It appears that this software is not compatible with the fusion hdtv drivers?

    MS please test your software before causing all of these problems. MCE should be simple just turn it on and it works. Like Replay TV or Tivo.

  12. Philip says:

    To “uninstall” kb890830, delete it from:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

  13. J. A. Richmond says:

    This is a great tool. It you leave the computer on for more than an hour, it now slows right down & eventually crashes. Particularly if you leave the computer searching for a document etc or your antivirus software is scanning.

    WORSE THAN THAT it has disabled my Kaspersky antivirus software from deleting known/dected viruses. KAV now reports the presence of a virus but viruses are left intact on the drive. You can’t rename, disinfect, delete them even when you tell KAV to do this manually. Everything was fine untill I downloaded the SODDING MICROSOFT tool as an update. The microsoft tool also disables real time scanning & keeps interfering with memory scanning. The FARCE is that with the Microsoft tool installed my computer has been laid open to all & every virus.
    Download the Microsoft tool only if you wish to catch a virus!
    The tool behaves very much like a virus. Maybe it should be added to the antivirus signature lists to prevent MICROSOFT from infecting computers. Really bloody marvellous! Even re-installing your antivirus software makes no difference. The MICROSOFT VIRUS still attacks Kaspersky & wrecks the operation of the computer.

    THanks for the registry tip above. Will try that to see if it gets rid of the MICROSOFT MALICIOUS VIRUS that they have infected my machine with!

  14. Val says:

    Delete (or rename) mrt.exe which can be found at \system32

  15. Val says:

    the full path is %windir%\system32\Mrt.exe

  16. TA says:

    MRT diabled about 2/3 of all my programs – including all the MS Office files! Don’t use it – if you have good anti-virus, IMHO you don’t need it.

  17. Santoz says:

    As Microsoft keeps on creating this type of stupid softwares, my thumbs are up for all those anti-microsoft hackers. Wait till Microsoft Vista comes for less than $1.

  18. Daniel says:

    Watch out! There’s a new, March 2006, version automatically downloaded as a Windows Update. It interfered with my ebay usage AND far, far worse stripped out my Norton Internet Security!!!

  19. crystallize says:

    I did a few windows updates among this one and now my computer is almost completely locked. It takes ages to open even the smallest thing or even a folder if it works at all ….

    I Don’t know what to do *sobs*

  20. Jim Gottlieb says:

    This was installed on my PC, ran without my permission, and decided that all our internal corporate programs were known viruses and removed them!

    When I complained to Microsoft they said it’s because we ran Windows Update without disabling our corporate firewall. I told them if we disabled our corporate firewall, all our Windows machines would be hacked. What morons!

  21. Peter says:

    I am not into abuse of the legal system, but this sounds like fodder for a class-action lawsuit. If one of us put an unwanted program on a Microsoft computer that had the same impact, we would be arrested!

  22. alvin says:

    According to the event log:
    Installation Ready: The following updates are downloaded and ready for installation. This computer is currently scheduled to install these updates on Sunday, December 17, 2006 at 10:14 AM: – Windows Malicious Software Removal Tool – December 2006 (KB890830)

    When this happens, my computer automatically reboots. Arrggg!

  23. AfterHour says:

    Hi i have the sdame problem as Elgin, but im on windows XP. I have made any kind of scan, llike vunerability, antivirus etc from my personal program and also from internet site like symantec. my computer is clean.
    the time i install malicious software removal tool from microsoft it crashed to a blue screen and then reboot.
    everything goes well since a roll back into system restore.
    still got to disable windows update and i want to remove the need to update it. i have this annoying red shield that ask me to install it. what can i do?

  24. Allan says:

    I initially saved the msrt to my desktop. After hearing all sorts of bad things about it I tried to uninstall the msrt by right clicking on the icon and chosing delete. A message appeared stating that it could not be deleted because the tool was in use by another program. After trying several things I then figured out that the program that was using the msrt was ME! So I ‘ctl-alt-deleted’, found “Microsoft Malicious…” in the processes menu and stopped it. I then went back to the msrt icon on my desktop and successfully deleted the tool. I ctrl-alt-deleted again and “Microsoft Malicious…” does not appear in processes anymore.

  25. lavy says:

    the views of everbody helped me decide against installing the software. thanks

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