(Moved to Livesafe - by Moderator)
While I emphatically recommend one to not (Turn off ) your McAfee Protection. In some instances,it is appropriate to do so for major system upgrades, Service Packs, etc.
Quite often one wishes to do so, in order to install a (Game) or have been requested to do so by the Site you are attempting to Download from. One has to use Caution doing so.
May I ask what feature you are inquiring about, and the reason for wanting to do so?
McAfee Volunteer Moderator
Assuming this is Windows you can turn off Real-time scanning temporarily by opening SecurityCenter (double-click the taskbar icon or open it from the Start Menu) and then go to Virus and Spyware Protection > Real-Time Scanning > turn off and tell it for how long.
As Catdaddy has said this normally is not necessary unless one is installing a major update such as a service pack, and you wont be protected during that period.