On 2013 Jul 19, at 17:38, Grappone Al <algrappone at comcast.net> wrote: > Can I trash the one in my app folder? You should trash whichever one says that it won't run. The easiest way to get the one you need, if you don't have it for some reason, is to copy it from another Mac running the same OS X version as you have. To avoid this problem, in the future, do not move Apple apps from the place where Apple installed them. Then they will be updated as necessary when you update Mac OS X. In recent Mac OS X versions, Activity Monitor has been in in /Applications/Utilities.