Based on @ttilley explanation in https://github.com/thibaudgg/rb-fsevent/issues/17, signal handlers registration should happen before any subprocess creation (fsevent_watch for instance) to be properly catches by the subprocess.

Note that in the case when guard is run via bundler, this –quoting @ttilley– "would make this an unsolvable problem" (isn't it dramatic?! ;)).

lib/guard.rb

@@ -24,9 +24,10 @@ module Guard
     end
 
     def start(options = {})
+      Interactor.init_signal_traps
+
       setup(options)
 
-      Interactor.init_signal_traps
       Dsl.evaluate_guardfile(options)
 
       listener.on_change do |files|

lib/guard/interactor.rb

@@ -37,7 +37,7 @@ module Guard
           stop
         end
       else
-        UI.info "Your system doesn't support INT signal, so Ctrl-C (stop) won't work"
+        UI.info "Your system doesn't support INT signal, so Ctrl-C (Stop) won't work"
       end
 
       # Reload (Ctrl-Z)