After upgrading OS X to version 10.4.x / Oxygen XML Developer to version 6.x Oxygen XML Developer is not associated anymore to the file types XML, XSL, XSD, etc. This worked in the previous version of Oxygen XML Developer. How can I create the file associations again?
The upgrade damaged the file associations in the LaunchService Database on your Mac OS X machine. Please rebuild the LaunchService Database with the following procedure. This will reset all file associations and will rescan the entire file system searching for applications that declare file associations and collecting them in a database used by Finder.
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister -kill -r -domain local -domain system -domain user