How to Fix: Malwarebytes MBAMService.exe High CPU Usage

Dennis Faas's picture

Infopackets Reader Ramona A. writes:

" Dear Dennis,

Recently My Windows 7 laptop kept popping up with 'Windows has detected that your computer's performance is slow' error messages. I disabled the color scheme to fix the issue (as recommended) but the popups kept coming every 3 minutes or so. I suspected I was infected with malware, so I downloaded Malwarebytes Antimalware and did a scan. MBAM found over 1,700 'threats' - one of them was a rootkit. I quarantined all the items, then rebooted and things are much better, however - now the 'mbamservice.exe' is constantly causing high CPU load. So I have effectively robbed Peter to pay Paul and the 'your computer is slow' error messages are still coming! I have waited over 10 minutes for the 'mbamservice.exe' to calm down, but it runs non-stop. I have tried reinstalling Malwarebytes Antimalware but it does not help. I do not want to remove Malwarebytes in case I need to scan for another infection. Can you please help? "

My response:

I asked Ramona if she would like me to connect to her machine using my remote desktop support service in order to have a closer look, and she agreed.

Everything Ramona said was true - the Malwarebytes service "mbamservice.exe" was running 25% of her CPU non-stop. The version she was using was 3.22 - the latest version available at the time of writing.

Before I get into the technical details about this issue, it should also be noted that Malwarebytes Antimalware now opts the user into the "Premium Trial" version as the program has been installed, which means that all of the protection offered by the "Premium Trial" is automatically turned on by default.

As a general rule of thumb, the more antimalware / antivirus "protection" you add to a PC, the more CPU processing is required to process any potential 'threats', which then translates to high CPU overhead (up to 25% CPU or more!) and a substantially slower system. This is especially true on older, slower hardware and may not be the case if you own a bleeding edge PC.

Troubleshooting: Malwarebytes MBAMService.exe High CPU Usage

At first, I tried disabling the "extra" protection offered by the Premium Trial version of Malwarebytes Antimalware, but this did nothing in terms of calming down 'mbamservice.exe' so that it wasn't running full tilt. I then tried shutting off the Premium Trial version of Malwarebytes and instead set Ramona's system to the "Free" version of Malwarebytes. Most of the time, this will fix the issue - however in Ramona's case, it made no difference.

Note that you can disable the Premium Trial by opening up the Malwarebytes Antimalware main window, click the Settings icon on the left, then click the "My Account" tab at the top, then click the open that says "Deactivate Premium Trial" near the bottom. Click here for a picture which shows exactly what I just said.

In the end, the only option that prevented the high CPU usage was to disable the Premium Trial (which sets Malwarebytes Antimalware to the "Free" version and with all the extra "protection" disabled), then set the Malwarebytes service to "Manual" (using Windows Services), then reboot the system. To set the service to manual: click Start, then type in "services.msc" (no quotes); click the "Services" icon when it appears. Scroll down the list until you see "Malwarebytes Service", double click it and then set "Startup type" to "Manual"; click Apply, OK, then reboot the system.

This effectively disables the "mbamservice.exe" from executing on reboot - which also disables any "active" protection. In other words, the only way to scan for malware is to do so manually - the exact same way you would do it if you were running the free version of Malwarebytes Antimalware. So, no functionality of the program has been lost, so long as you aren't paying for the premium service which uses real time, automatic scanning - I will discuss more about that further down.

In order to run a manual scan of Malwarebytes Antimalware, Ramona would have to go to the Windows Services (click Start -> type in 'services.msc'), then enable the Malwarebytes Service, then launch Malwarebytes Antimalware icon from the desktop, then perform a manual scan.

A Temporary, Band-Aid Fix

The solution I provided Ramona is only a band-aid fix to the problem, as it does not address "Why is Malwarebytes Antimalware eating 25% of my CPU 100% of the time?" As such, I will address that now.

Usually when I see issues like this, it's because the PC has suffered irreversible damage from malware. Yes, the malware is gone, but it's now corrupted the system, which causes Windows to misbehave - just as we see in this case. A good analogy might be that you get rear-ended in a car accident and the car is repairable, but never runs the same even after being fixed.

In situations like this, the only way to truly fix the issue is to do a clean install of Windows. Nine times out of 10 this fixes the problem, but not everyone will want to go about that path because it is a huge pain to backup all your files, reinstall Windows, re-import user data, reinstall programs, and tweak the system. If you dread this - I am more than happy to assist you using my remote desktop service - described next.

Additional 1-on-1 Support: From Dennis

This article is proof that not all solutions have a happy ending - though, sometimes it is possible to mitigate the problem to find a happy medium. If you are struggling with Malwarebytes Antimalware constantly eating your CPU and making your computer painfully slow, you can try disabling the Premium Trial version, and if that doesn't work, try setting the service to manual as described in this article.

If you've paid for the premium service of Malwarebytes Antimalware and you wish to have real time automatic scanning on 24/7 - and without Malwarebytes eating your CPU all the time, making the computer painfully slow - you may be looking at a Windows reinstall to fix the problem.

If that is the case, and you dread reinstalling Windows - I would be more than happy to meet with you to discuss the issue in further detail using my remote desktop support service. While connected, I will look at your system to determine the best course of action to take. Simply contact me, briefly describing the issue and I will get back to you as soon as possible.

Got a Computer Question or Problem? Ask Dennis!

I need more computer questions. If you have a computer question -- or even a computer problem that needs fixing -- please email me with your question so that I can write more articles like this one. I can't promise I'll respond to all the messages I receive (depending on the volume), but I'll do my best.

About the author: Dennis Faas is the owner and operator of With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.

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topaz1943's picture

Having run MWB successfully for a number of years, and reading about the many problems caused by the most recent versions, I was still foolish enough to install MWB 3.2. My disk usage immediately went to 100% and the PC became almost unusable. I ran the MWB cleanup program but it did not completely remove MWB. I was unable to manually remove traces in the registry.
Almost at the point of a Windows reinstall (a 3 day job to reinstall programs etc), but without further intervention the problem resolved itself and disk usage normalised.
In view of the many problems reported by users, I would be wary of recommending this software.

grahroll_4889's picture

An in-place upgrade/update can also fix many issues. You should still back up your data but it can save lots of re-installing many other programs and licences.

topaz1943's picture

I have successfully performed an in-place upgrade on Windows several times, and agree that it saves an enormous amount of time. However I was loathe to do it this time as I have a major workload at the moment, and was concerned that the process might fail and cause a lot of down-time.

Focused100's picture

I have done a few non-destructive reinstalls of Windows 7 which preserves all the settings and installed programs.

Have you run across a way to do that in windows 10?

Dennis Faas's picture

The only way to do that is from the desktop using an ISO. You cannot do a 'repair install' by rebooting using a DVD or USB. I have no idea why Microsoft decided on this policy but previous editions of Windows could do it.

For what it is worth, I have had limited success doing repair installs on severely corrupted systems. Also a repair install always resets licenses on MS Office (and other programs), which means you will need to call Microsoft support to get it sorted - and that's if they can fix it. I had a customer that had this issue after doing a repair install - MS Office would NOT register no matter how hard she tried (and that was with MS support)! The only way to fix it was to do a clean install of Windows. Sometimes it's easier (and faster) to start fresh with a guaranteed working system.

topaz1943's picture

Wise advice. That is why I was reluctant to try an in-place upgrade with Windows 10. While I have had no problems with Windows 7 in-place upgrades, I am not as confident with Windows 10.
I did come across this site:
however I opted not to try it.

Focused100's picture

I watched a few youtube videos that the site you recommended had links for.
It seems as straight forward as the Win 7 procedure.
I believe as long as you do a complete backup before you begin it may be worthwhile to solve intractable Win 10 BSDs.

Sparkydog's picture

Keep MWB on manual and install ESET NOD32. It uses almost no resources and catches everything. The best a/v in the business. I have used it for several years, but, of course, it's not free.
The biggest problem I see are people using the free stuff from the internet.
They invest in a $1000 computer, but cheap out on the antivirus and other kinds of software.