The message “Unable to load Java Runtime Environment” means that the Mac computer cannot load JRE, either because it is out of date or (more usually) because it has not yet been downloaded and installed . It can also happen after the computer OS X has been updated, e.g. to 10.14 Mojave from 10.13 Maverick.
Read moreHow do I fix Java Runtime not found?
Enable the latest installed version of Java in the Java Control Panel
Read more