If you’re running Mac OS you might have lots of duplicate entries in your “open with” menu. Thanks to a quick Google I found this post which details the fix, which, is nice and simple!
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user
You’ll need to the relaunch /force quit finder or reboot.
Only issue I had was a couple of default “open with” options had reset, but, get info on those types and reset takes no time at all.