What is MPSigStub.exe?

The .exe extension on a filename indicates an executable file. Executable files may, in some cases, harm your computer. Therefore, please read below to decide for yourself whether the MPSigStub.exe on your computer is a Trojan that you should remove, or whether it is a file belonging to the Windows operating system or to a trusted application.

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MPSigStub.exe file information

Windows Task Manager with MPSigStub
MPSigStub.exe process in Windows Task Manager

The process known as Microsoft Malware Protection Signature Update Stub belongs to software Microsoft Malware Protection by Microsoft (

Description: MPSigStub.exe is not essential for Windows and will often cause problems. The MPSigStub.exe file is located in the C:\Windows\System32 folder. Known file sizes on Windows 10/8/7/XP are 247,976 bytes (40% of all occurrences), 374,944 bytes and 8 more variants. 
The program is not visible. The file has a digital signature. It is not a Windows system file. MPSigStub.exe is able to monitor applications. Therefore the technical security rating is 4% dangerous, however you should also read the user reviews.

Uninstalling this variant: If you are having problems with MPSigStub.exe, you can do the following:
  1) remove the entire program Microsoft Corp. using Windows Control Panel
  2) ask the software vendor,, for advice.

Recommended: Identify MPSigStub.exe related errors

Important: Some malware disguises itself as MPSigStub.exe, particularly when not located in the C:\Windows\System32 folder. Therefore, you should check the MPSigStub.exe process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

The Forefront Client Security Antimalware Service updates the anti-malware engine files and the anti-malware definition files without leaving a gap in malware protection.
  Neil Tunnah   (further information)
It is part of the Windows Automatic Update tool.
  Sean Smith  
MpSigStub.exe is a Microsoft installer application used in conjunction with Windows Automatic Updates. It extracts update files to a temporary directory.
Microsoft Malware Protection Signature Update Stub
  Microsoft MVP   (further information)
It is required for Microsoft Windows Defender and I believe it is also needed for Microsoft Malware Removal Tool that is updated monthly. It is not Virus, Malware, Trojan, etc. When detected as such, report it as a false positive.
  Jenni L   (further information)
MpSigStub.exe is a MS installer application used in conjunction with Windows Automatic Updates. It extracts update files to a temporary directory.
  Alex   (further information)
MS Defender, MSMWRT, & Panda Cloud AV don't detect; McAfee does
stored in a random folder (in my case: E:\63bf18e751d3d39be7b19e12)
It was flagged by Bullguard as suspicious as it attempted to make a registry change
it is in a long random named folder started 2 days ago, i do not need it before so its trash
stored in an invisible folder on external hard drive I pluged in 3 secondes earlier, then realized it was the wrong hardrive, and tried to eject it. Zentimo said MpSigStub.exe was preventing the drive from ejecting, because it was running from a folder that did not exixt on the hard drive.
I believe there is a "real" file names MPSigStub" however mine was located in a random letter/number filename... deleted
on my pc it comes up automatic and seems to freeze the games that i am am playing which is very annoying
  bek strelley  
Mine is a virus. I had it in a random letters and numbers folder and now I can't delelte it.
It usually gets into my harddrive for some reason after i uninstall Norton. I can't remove it without network access authority.
I can neither conferm its danger or its harmlessness. I can not delete it from a second HDD fitted to my PC to hold lossless music files. I did manage to delete it earlier in the year by reformatting the HDD before reinstalling the lossless music files but as soon as Microsoft Updates came back in it reinstalled on the separate HDD.
It's in that folder in the root of c drive that not a suitable temporary location to be picked up by Disk Cleaner. Deleted.
It is in a randomly numbered folder on my secondary drive and I can't simply deleted. It says I need admin access but its my home computer
Mpsigstub.exe is store in a folder named 0a83a9928b30c2eebcbbb8 on my local disk (c) when i tried opening the folder it said i needed admin permissions. dont know if i should delete it or leave it. but by all these comments i might just keep it.
  Fernando L  
Remove it as sun as possible! In my case, there was USB device in control.
SpyHunter caught it and inquired. It is a Malware hunting program.
I cannot delete it, says I need Network Service permission, whatever that is...
If i try to delete this contain folder it said "you require permission from NETWORK SERVICE to make change to this folder
It somehow got into my Seagate backup drive and resists all attempts at removal; MpSigStub.exe is in a self-created folder named ae7199970d6a0fe68f55f50c513ef6 . The unusual nomenclature and resistance to deletion makes it highly suspicious to me, especially since I have experienced virus infections that may not have been totally removed by anti-virus applications
As some have already said it is used in conjunction with Windows updates. It is not a threat but it is possible that some malware disguises itself thus.
It's in a random directory with a name "37952e3e1d0c66dac7fd7deb896e75a6". SpyHunter4 flags it and asks whether it should block execution of this executable. I say yes, permanently, but it seems to be flagged later on many times. The directory requires admin privileges even to look inside. I can't delete the file regardless of what changes I make in "properties." Nothing in "properties" indicates it a MS file, which it obviously isn't. I was able to delete the file by using the command prompt, cd \, cd dir name , dir mp*.*, del mp*.* There was another folder C:\33d51bc59ba64b06bf82dcd8 with this executable and two other files with extension VDM. I deleted these in the same way with del *.* Both folders could be deleted thru Windows Explorer. The folder names are probably random and unique names. There's another folder with a similar but shorter name. A file MRT.exe is inside. I was able to delete that through Explorer, as well as its folder. I don't know if they're related files but I figured such odd folder names were fishy as were the executables with no source ID and, in the MpSigStub files' case, making it impossible for me as admin to delete thru Explorer.
  Richard Ong  
I suppose MS installs it somehow (from a cabinet?) if you delete MS Security Essentials. It then keeps the data harvest flowing that MS would collect otherwise with MS SE. Its is spyware - a harvester - but only dangerous for your privacy
Suddenly appeared on my non-windows partition that acts as a seperate HDD in a folder named by a long string of random numbers and letters. Gonna delete it as I have no idea what it is.

Rating chart

Summary: Average user rating of MPSigStub.exe: based on 31 votes with 28 user comments. 7 users think MPSigStub.exe is essential for Windows or an installed application. 4 users think it's probably harmless. 9 users think it's neither essential nor dangerous. 5 users suspect danger. 6 users think MPSigStub.exe is dangerous and recommend removing it. 8 users don't grade MPSigStub.exe ("not sure about it").

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Best practices for resolving MPSigStub issues

A clean and tidy computer is the key requirement for avoiding problems with MPSigStub. This means running a scan for malware, cleaning your hard drive using 1cleanmgr and 2sfc /scannow, 3uninstalling programs that you no longer need, checking for Autostart programs (using 4msconfig) and enabling Windows' 5Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the 6resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the 7DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the MPSigStub.exe process on your computer, the following programs have proven to be helpful: ASecurity Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. BMalwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

MPSigStub.exe [all]