Without going into much depth, "Mpk.exe" is reported to be (Malicious) and a Keylogger. This is why McAfee detected it. Are you trying to Download a Game, for example? As much as we desire to insist on doing so, even though our Protection guards us against said such executables.
It could in almost all cases, lead to Chaos on our systems.
I,ve not the time at the moment, to run it through Trusted Source,Virus Total,and other reputable Sites for reputation-and description of this process, yet for the time being,simply "Google the process" and you yourself will see what it says.
Actually you can see that Norton-Symantec,Avast detects this as a "Rootkit-Keylogger" as each Security Vendor has their own names -classifications for each Detection. MPK.EXE seems to be related to the program "My Pop-up Killer" by "Nirsoft" You can find out more about this process HERE
This is from the Microsoft Malware Encyclopedia HERE
I might add also, if you have somehow already installed this process, it can be removed by Downloading/Installing Malwarebytes (Free) Version only. Do not accept the (Free Trial Offer) or activate the (Pro) Version. This will cause a conflict with your McAfee Software, due to the RTS Module.
The ( Free ) Version will suffice for Detection/Removal. You can find this and other Superb (Free) Tools below my Signature-(Second Link)