Why does "Open With" display so many instances of an app? [duplicate]

Rebuild LaunchServices to Fix Duplicate Entries in OS X’s ‘Open With’ Menu

To fix this, we need to reset OS X’s LaunchServices database. As is the case with most actions in OS X, there are multiple ways to accomplish this task, but the fastest is to simply use a Terminal command.

From that article- Copy following in to your Terminal

/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user

This is a long-standing bug in OS X. You can fix it with lsregister:

/Sy*/L*/Fr*/CoreS*/F*/L*/S*/lsregister -kill -r -domain local -domain system -domain user

In addition to the other answers, it can show multiple copies that exist on other hard drives or backup copies. An external hard drive that you use for Time Machine backups may show up as an option if your Applications are backed up to that drive.

If you're curious where the apps are coming from, open up one of the other applications. Then from the Dock, control+click on the apps icon and choose: Options > "Show in Finder". This will show you where the application is.

Use the command line provided by Buscar웃 to update your system's LaunchServices.