diff --git a/internal/audio/recorder.go b/internal/audio/recorder.go
index 402af36..d75c89f 100644
--- a/internal/audio/recorder.go
+++ b/internal/audio/recorder.go
@@ -130,6 +130,30 @@ func (r *Recorder) Start(fromDev, micDev string, prerollSec int) error {
 	if prerollSec < 0 {
 		prerollSec = 0
 	}
+	// Does the configured endpoint still EXIST?
+	//
+	// Endpoint ids are stored, and a DAX channel that is reconfigured, disabled
+	// or removed comes back with a different id. The old one then opens without
+	// complaint on some drivers and simply never streams — which is
+	// indistinguishable from a quiet band until the recording turns out empty.
+	// Checking the list takes milliseconds and answers it outright.
+	if devs, derr := ListInputDevices(); derr == nil {
+		known := func(id string) bool {
+			for _, d := range devs {
+				if d.ID == id {
+					return true
+				}
+			}
+			return false
+		}
+		if fromDev != "" && !known(fromDev) {
+			LogSink("recorder: the configured radio input no longer exists (%s) — re-select it in Settings → Audio", fromDev)
+			AlertSink("The configured radio audio input no longer exists — re-select it in Settings")
+		}
+		if micDev != "" && micDev != fromDev && !known(micDev) {
+			LogSink("recorder: the configured microphone no longer exists (%s) — re-select it in Settings → Audio", micDev)
+		}
+	}
 	r.prerollSamples = prerollSec * sampleRate
 	r.twoSrc = micDev != "" && micDev != fromDev
 	r.stopCh = make(chan struct{})