After upgrading macOS and Oxygen XML Author Eclipse plugin, it is no longer associated to the appropriate file types (such as XML, XSL, XSD). How can I re-create the file associations?
The upgrade damaged the file associations in the LaunchService Database on your macOS machine.
Run the following command in a Terminal:
/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/lsregister
-kill -r -domain local -domain system -domain user
Restart Finder with the following command:
killall Finder
Result: When you start Oxygen XML Author Eclipse plugin, the file associations should work correctly.