Where is the preference list for "open with" applications? I'm getting an (error code -10813) when trying to set file extensions to open with a certain app in Mountain Lion 10.8.5. Where is the plist file that has those preferences so that I can delete it and hopefully end this problem?
See the answer for Why does my Mac's list of “Open with” applications start listing the apps twice and sometimes three times?:

This happens because the LaunchServices database gets corrupted.
To fix on Mountain Lion:

Open Terminal.app in the /Applications/Utilities/ folder.
run /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain system -domain user
Restart

This hint on Mac OS X Hints covers the command for other Mac OS versions over the years.