If you’ve ever used the “Open With … ” contextual menu item in Finder in OS X, you may have seen several duplicates of programs that are listed there. It’s confusing and cluttered. There is a buried application to reset this particular list called
lsregister. Open up a Terminal window and copy and paste the following:
/System/Library/Frameworks/CoreServices.framework/Versions/A/ \ Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill \ -r -domain local -domain system -domain user
Now your Open With list should be rebuilt with just the current apps in /Applications and possibly ~/Applications. This tip was originally found at Apple Discussions, but the location of
lsregister has changed since then.
Often times when migrating systems or generally screwing around in OS X, you may find that, among other things, OS X gets confused by what applications you want to use by default.