Has your CPU been at 100% utilization lately? If you went to Windows Task Manager and looked at the Processes tab, you might have noticed that a process called msmpeng.exe is eating up all available CPU.
So what is msmpeng.exe and how to prevent it from slowing down your system? Well, unlike what you may have read elsewhere, this is not spyware or malware. This is actually quite ironic because it is related to Windows Defender, an antivirus product from Microsoft.
Windows Defender is an essential antimalware and virus protection program for Windows and should not be disabled unless you have a third-party program installed. In this case, it turns off automatically.
In this article, I will go over the various reasons it might be using your processor and what you can do to fix it.
If you accidentally glanced into Task Manager while Windows Defender was scanning, it is obvious that it will take a lot of CPU cycles. Wait for the scan to complete and check the processor load again. Hope everything is back to normal.
Unfortunately, you cannot change the scheduled scan time for Windows Defender. It should only scan when the computer is idle and outside of business hours. However, if you turn off your computer, it can scan while you are using it.
Most automatic scans shouldn’t take that long, so if you see your PC running slowly for a long time, it is possible that Windows Defender is spending a lot of time scanning a directory or process that doesn’t need to be scanned. This brings us to the next possible solution.
Exclusions from the survey
The best way to figure out what to exclude is to run a full scan and see how it looks at all the items on your computer. When you see that it takes a long time in a certain directory or when scanning a certain process, you can add that to the exclusion list.
You can do this by going to Virus & Threat Protection, then to Virus & Threat Protection Settings, and finally by clicking Add or Remove Exclusions.
You can add a file, folder, file type or process to the exclusion list. After adding the problematic items to the list, the time required to complete the scan should be significantly reduced.
Turn off Windows Defender
Another option is to just turn off Windows Defender, which I don’t recommend unless you need to. Another option before permanently disabling Windows Defender is to install a third-party antivirus program. When you install another antivirus product, Windows Defender is automatically disabled so that the two programs don’t interfere with each other.
There are several ways to disable Windows Defender on your computer. On Windows 10, Microsoft doesn’t really want you to do this, so the only option you have in the Security Center is to temporarily disable real-time protection.
Another way is to edit the registry setting. Open regedit on your computer (click Start and type regedit) and navigate to the following directory:
HKEY_LOCAL_MACHINE SOFTWARE Policies Microsoft Windows Defender
Create a new DWORD (32-bit) value named DisableAntiSpyware and give it decimal value 1. Restart your computer and Windows Defender should be disabled. You can remove this key or change the value to 0 later to re-enable Windows Defender.
The second way to permanently disable Windows Defender is to use Group Policy, which will only work on Windows 10 Pro or later. Click Start, type gpedit.msc and hit Enter. Navigate to the following folder:
Computer Configuration – Administrative Templates – Windows Components – Windows Defender Antivirus
In the right pane, you will see the option Turn off Windows Defender Antivirus. Double click on it and select the “Enabled” radio button.
Hopefully, you don’t need to turn off Windows Defender as it usually protects your PC well from malware and viruses. If you have any problems or none of the above helped, let us know in the comments and we will try to help. Enjoy!