Nagios Support Forum

Is there an easy way to reset the installation removing all installed hosts leaving the rest of the configuration (host groups, service groups, contacts, time periods, etc) alone? Thanks!

You can do this via the Core Config Manager by simply selecting all the hosts and choosing the "Delete" option under "With checked":
Though you would first want to remove all the services defined for each host and make sure there are no hostgroup/servicegroup dependencies that exist. In other words, you would need to remove all members of your hostgroups/servicegroups since you're deleting all the hosts/services.