After upgrading license from free to enterprise, the default search dashboard displayed no data.
Search on Splunk Answers revealed nothing specific to this problem.
Found a related problem in this answer, and turns out if you check out the user roles and mistakenly click on something then try to use the browser back button, you may still change some of the default settings.
In user roles, make sure to set "Indexes searched by default" to include whichever indices you want searched in dashboard_live.
In user roles, make sure to set "Indexes searched by default" to include whichever indices you want searched in dashboard_live.