ODK aggregate installation in Mac v10.13.6

Very interesting. It seems to me that something is broken with your Java install. Maybe $JAVA_HOME isn't configured properly.

I don't know if this will work, but can you try uninstalling both Java 8 and Java 10. Reboot, re-install Java 10, then try installing Aggregate.

And since you have shared your token in this topic, be sure to delete it and get another!