To make sure that’s not the case, you’ll need to deploy a deep scan with a capable anti-malware utility. The MsMpEng.exe file might actually be malware posing as a system process in order to be allowed to tap into the system’s resources. Malware infection – As ironic as this might sound, a high CPU usage by the security file MsMpEng.exe can also signal a virus infection.This will be effective in scenarios where Windows Defender was re-activated after a long period where another 3rd party antivirus was active.

Internal Windows Defender conflict – This might seem like a weird fix, but a lot of users have confirmed that once they’ve added MsMpEng.exe to the exclusion list of Windows Defender, the CPU consumption went down drastically.

To address this problem, you’ll need to open up the Registry Editor and modify the value data of the DisableAntiSpyware key.

The antiSpyware function is ON – According to a lot of Windows 10 community insiders, this problem might be caused by a Registry key that remains disabled despite the fact that Windows Defender is no longer the active antivirus.In this case, you will need to forcibly turn off Windows Defender – either via the Local Group Policy Editor or via Registry Editor. This usually happens when you’re using a security solution from a smaller company that is not yet verified by Microsoft. Windows Defender is overlapping – As it turns out, another scenario where you can expect this issue is when Windows Defender is actually overlapping another 3rd party antivirus that is currently active.

To address this issue, you’ll need to use the Task Scheduler to tone down the frequency of the task that summons the MsMpEngprocess. The task frequency of MsMpEng is too high – According to a lot of affected users, a frequent reason why you’ll end up seeing this behavior is when an administrative task related to MsMpEng runs at very frequent intervals.In this case, you can either use a 3rd party repair utility to get the issue fixed or you can go for a repair install. File corruption affecting Windows Defender – One of the first scenarios that you should troubleshoot against is a scenario in which the reason why you are seeing this massive CPU usage is due to some type of corruption affecting the Windows Defender component.

Antimalware service executable