mcupdate.exe is a process belonging to McAfee Internet Security suite.
This process ensures the computer's virus definitions are up to date by connecting to McAfee's server on the Internet. This program is important for the stable and secure running of your computer and should not be terminated.
Non-system processes like mcupdate.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues