It seems after cloning a DB, subsequent queries take a very long time (perhaps infinite?)
I did (with the Movie DB) MATCH (p:Person) RETURN p
for which the browser shows "Started streaming 132 seconds after 7 ms and completed after 92 ms"
I then went to the Desktop, clicked on the three dots and choose the menu item "Clone". After waiting for the clone to finish, then I reran the query which still hasn't finished. The problem seems to go away after you quit Neo4J app and start again.