Reset the Launch Services database.
Syntax lsregister: [Options] [path...] [-apps domain[,domain]...] [-libs domain[,domain]...] [-all domain[,domain]...] Options -kill Reset the Launch Services database before doing anything else
-seed If database isn't seeded, scan default locations for applications and libraries to register
-lint Print information about plist errors while registering bundles
-convert Register apps found in older LS database files
-lazy n Sleep for n seconds before registering/scanning
-r Recursive directory scan, do not recurse into packages or invisible directories
-R Recursive directory scan, descending into packages and invisible directories
-f force-update registration even if mod date is unchanged
-u unregister instead of register
-v Display progress information
-dump Display full database contents after registration
-h Display help
Paths are searched for applications to register with the Launch Service database.
Valid domains are "system", "local", "network" and "user". Domains can also be specified using only the first letter.
The Launch Service database controls the contents of the 'Open With' contextual menu.
lsregister is not on the system path so run it using the full path as below.
Run lsregister and display help
Reset the local, system and user domains:
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain system -domain user
This will also reset the first-launch security prompt: the first time you launch an application by opening a document, the system will ask 'are you sure'.
“Because the people who are crazy enough to think they can change the world, are the ones who do” ~ Apple Advert
Onyx utility - Includes a maintenance script to rebuild the Launch Services (use this to remove duplicate entries).
Article: TA24770 - Clear the 10.4 Finder "Open With" contextual menu (rename /Library/Preferences/com.apple.LaunchServices.plist).