When you right click on any item (excluding Folders) in Finder you have the option to pick which applications you want to open the file with. For example with a text file you could open the file in TextEdit, Word and Pages to name a few. Depending on the type of file you are selecting you may have the option of a couple of applications to choose from, or many. Every so often this menu gets cluttered with duplicate items. It doesn’t happen very often but it is really annoying when it does. This tip is going to show you how to remove the duplicate items.
Open Terminal located in Applications > Utilities. In the Terminal window, copy and paste the following into the Terminal window.
-kill -r -domain local -domain user;
The first line will delete the duplicate items from the menu. The second option will stop Finder and relaunch it, thus allowing the Open With menu to be repopulated with the correct, and non duplicate items. Note the backslash (\) allows a new line so it will fit onto the webpage. Normally this will be one long line.
Its only a simple command. However, for those using Mountain Lion or some older versions of Mac OS X, this trick will work easily in removing those duplicate items. I have only ever used this command twice since I have owned a Mac (since 2008), so its one you may never use.