Default App works better if Mac OS Easy Open is installed (even if it’s turned off). It will work anyway now, but document kinds may not be displayed correctly.
Mac OS Easy Open is not installed.
Some system-level data structures used by Default App are corrupt for some reason. Try rebooting the computer and see if the problem goes away.
Default App has a problem.
Some software is conflicting with the operation of Default App. To avoid further problems, Default App will disable itself until the conflicting software is removed.
Default App can’t work on this system.
The version of Default App that loaded at startup is newer than the one you’re trying to use now.
A newer version of Default App is already running.