I ran into a hang today with only ivy enabled and nothing else configured or installed. The behavior was such that after I typed a hostname with a TLD (such as not.existant.com1), then typed C-x d to visit a directory or C-x C-f to find a file, Emacs would hang. My mouse would turn into a pin-wheel. My only recourse was to send the ‘quit’ command via C-g to cancel the operation.