diff --git a/app.go b/app.go
index 8d5b632..1a9aa9b 100644
--- a/app.go
+++ b/app.go
@@ -10681,6 +10681,11 @@ func (a *App) AudioStartMonitor() error {
 		return fmt.Errorf("audio not initialized")
 	}
 	cfg, _ := a.GetAudioSettings()
+	// Idempotent: asking to listen while a monitor is already running restarts
+	// it instead of refusing. The refusal surfaced as a checkbox that unticked
+	// itself the instant it was ticked, whenever the UI's idea of the state and
+	// the real monitor had drifted apart.
+	a.audioMgr.StopMonitor()
 	// When the rig's audio arrives over the NETWORK (Icom 50003), the monitor
 	// must be render-only: this button used to start a USB capture from the
 	// "From radio" device as well, and that second producer — often another