diff --git a/src/components/useMicrophoneLevel.test.tsx b/src/components/useMicrophoneLevel.test.tsx
index cb8e7bd47..1fb15ba2a 100644
--- a/src/components/useMicrophoneLevel.test.tsx
+++ b/src/components/useMicrophoneLevel.test.tsx
@@ -227,6 +227,33 @@ describe("useMicrophoneLevel", () => {
     expect(result.current).toEqual({ type: "unavailable" });
   });
 
+  test("a capture is released when the audio graph fails to build", async () => {
+    const { stream, stop } = fakeStream();
+    vi.stubGlobal("navigator", {
+      mediaDevices: { getUserMedia: vi.fn().mockResolvedValue(stream) },
+    });
+    // Whatever the browser does after the microphone is already open.
+    vi.stubGlobal(
+      "AudioContext",
+      class {
+        public constructor() {
+          throw new Error("no audio backend");
+        }
+      },
+    );
+
+    const { result } = renderHook(() =>
+      useMicrophoneLevel("mic-1", true, STEPS),
+    );
+    await waitFor(() =>
+      expect(result.current).toEqual({ type: "unavailable" }),
+    );
+
+    // Otherwise the microphone stays open, and its in-use light on, behind a
+    // meter that says it is unavailable.
+    expect(stop).toHaveBeenCalled();
+  });
+
   test("a missing microphone is reported as absent, not as silence", () => {
     const getUserMedia = vi.fn();
     vi.stubGlobal("navigator", { mediaDevices: { getUserMedia } });
diff --git a/src/components/useMicrophoneLevel.ts b/src/components/useMicrophoneLevel.ts
index b68b326b9..723a02efd 100644
--- a/src/components/useMicrophoneLevel.ts
+++ b/src/components/useMicrophoneLevel.ts
@@ -82,8 +82,8 @@ export function useMicrophoneLevel(
     let context: AudioContext | undefined;
     let frame: number | undefined;
 
-    const dispose = (): void => {
-      disposed = true;
+    /** Gives back whatever has been acquired so far. */
+    const release = (): void => {
       if (frame !== undefined) cancelAnimationFrame(frame);
       stream?.getTracks().forEach((t) => t.stop());
       // close() rejects if the context is already closed, which is possible if
@@ -94,6 +94,11 @@ export function useMicrophoneLevel(
       frame = undefined;
     };
 
+    const dispose = (): void => {
+      disposed = true;
+      release();
+    };
+
     navigator.mediaDevices
       .getUserMedia({ audio: { deviceId: { exact: deviceId } } })
       .then((acquired) => {
@@ -137,6 +142,11 @@ export function useMicrophoneLevel(
       })
       .catch((e: unknown) => {
         if (disposed) return;
+        // The microphone may already be open: building the audio graph can
+        // fail after getUserMedia has resolved, and the capture would then
+        // outlive its own failure, holding the microphone-in-use indicator on
+        // behind a meter that says the microphone is unavailable.
+        release();
         rootLogger
           .getChild("[useMicrophoneLevel]")
           .warn("Could not open microphone for level metering", e);