MsMpEng.exe is using about 50% of my CPU cycles. I tried to kill it with Task Manger, but the system said I was not authorized although I am running as administrator.
How do I kill and then disable this process? I will use Malwarebytes as my malware protection.
Thanks for the solution upon which all of you agree. Since this appears to be a problem that MS did not adjust with both Essentials and Defender, I am going to follow Oron J's suggestion and, and return to Avira.
Try the suggestions here: http://www.majorgeeks.com/news/story/fixing_the_high_cpu_usage_perfomance_of_microsoft_security_essentials_and_windows_defender.html.
As Hovsep points out, this is one of the main components of Microsoft Security Essentials, and this is a fairly common problem with it (see for example http://answers.microsoft.com/en-us/protect/forum/mse-protect_scanning/msmpengexe-running-at-95-cpu-usage/4b079063-e93a-4e80-935b-c1d7ee02a672).
Since MS Security Essentials is one of the least effective antivirus products available at the moment, I suggest you uninstall it and install a better program, such as Avast, AVIRA or BitDefender (free versions are available for each of them).
maybe you have Microsoft Security Essentials on your pc? you can uninstall and reinstall
add the following in exclusion list within Mcrosoft Security Essentials
c:program filesmicrosoft security essentialsMsMpEng.exe
C:Documents and SettingsAll UsersApplication DataMicrosoftMicrosoft Antimalware
C:Documents and SettingsAll UsersApplication DataMicrosoftMicrosoft Security Essentials
C:Program FilesMicrosoft Security Essentials
so you have to Open Microsoft Security Essentials, click the Settings tab and select Excluded files & locations, and then use the Add button to select files, folders, or drives.