Mac OS: fix duplicated Open With entries

/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain user;killall Finder;echo "Open With has been rebuilt, Finder will relaunch"

see also

• Remove Duplicates from the “Open With” Right-Click Menu in Mac OS X