diff --git a/apps/x/apps/main/src/meeting-detect/probe-macos.ts b/apps/x/apps/main/src/meeting-detect/probe-macos.ts
index 8917acdf..ea5bbdc4 100644
--- a/apps/x/apps/main/src/meeting-detect/probe-macos.ts
+++ b/apps/x/apps/main/src/meeting-detect/probe-macos.ts
@@ -1,82 +1,20 @@
-import { spawn } from "node:child_process";
+import { execFileSync } from "node:child_process";
 import type { MicProbe, MicUser } from "./types.js";
 
-// macOS doesn't expose a public "who is using the mic right now" API. Two
-// pragmatic signals we can read from a shell without a native helper:
-//
-//   1. `pmset -g assertions` — apps in a video call almost always hold a
-//      PreventUserIdleDisplaySleep wake-lock to keep the screen on. Strong
-//      proxy for "active call." False positives: video playback (YouTube,
-//      Netflix) — Phase 2's tab-title check filters those out for browsers.
-//
-//   2. `lsof | grep coreaudiod` — clients connected to coreaudiod. Noisy and
-//      doesn't always include the mic user, so we prefer pmset as primary.
-//
-// Output format from `pmset -g assertions`:
-//   pid 4711(zoom.us): [0x00000ff...] 00:23:14 PreventUserIdleDisplaySleep named: "..."
-//   pid 664(Google Chrome): [0x...] 00:00:59 NoIdleSleepAssertion named: "WebRTC has active PeerConnections"
-//
-// We key on two assertion types:
-//   - PreventUserIdleDisplaySleep — native meeting apps keep the screen on
-//     during a call. We deliberately do NOT match PreventUserIdleSystemSleep,
-//     which is held by `caffeinate`, `powerd`, downloads, etc. (noise).
-//   - NoIdleSleepAssertion — browsers (Chrome/Arc/Safari/etc.) hold this with
-//     the reason "WebRTC has active PeerConnections" whenever a WebRTC call is
-//     live (Google Meet, Zoom web, Teams web, Discord, Slack huddles). This is
-//     the most reliable browser-meeting signal. False positives (e.g. a WebRTC
-//     YouTube tab) are filtered downstream by browser-match's tab-title check.
 const ASSERTION_LINE = /^\s*pid\s+(\d+)\((.+?)\):\s+\[[^\]]+\]\s+\S+\s+(PreventUserIdleDisplaySleep|NoIdleSleepAssertion)/;
 
-const PMSET_TIMEOUT_MS = 10_000;
+const PMSET_TIMEOUT_MS = 4_000;
 
-// Run `pmset -g assertions` and resolve its stdout.
-//
-// We use spawn (not execFile) with stdin explicitly set to "ignore" because in
-// a packaged .app launched from Finder — rather than a terminal — the main
-// process has no valid stdin file descriptor. execFile would try to wire the
-// child's stdio to that invalid fd, and since this runs repeatedly from the
-// detector's background poll loop, the spawn fails with `EBADF` (errno -9).
-// Setting stdio to ['ignore', 'pipe', 'pipe'] points the child's stdin at
-// /dev/null, so no invalid descriptor is ever inherited. (This never surfaces
-// in dev because launching from a terminal provides a valid stdin.)
-function runPmsetAssertions(): Promise<string> {
-    return new Promise((resolve, reject) => {
-        const child = spawn("/usr/bin/pmset", ["-g", "assertions"], {
-            stdio: ["ignore", "pipe", "pipe"],
-            windowsHide: true,
-        });
-
-        let stdout = "";
-        let stderr = "";
-        let settled = false;
-
-        const timer = setTimeout(() => {
-            if (settled) return;
-            settled = true;
-            child.kill("SIGKILL");
-            reject(new Error(`pmset timed out after ${PMSET_TIMEOUT_MS}ms`));
-        }, PMSET_TIMEOUT_MS);
-
-        child.stdout?.on("data", (chunk) => { stdout += chunk; });
-        child.stderr?.on("data", (chunk) => { stderr += chunk; });
-
-        child.on("error", (err) => {
-            if (settled) return;
-            settled = true;
-            clearTimeout(timer);
-            reject(err);
-        });
-
-        child.on("close", (code) => {
-            if (settled) return;
-            settled = true;
-            clearTimeout(timer);
-            if (code === 0) {
-                resolve(stdout);
-            } else {
-                reject(new Error(`pmset exited with code ${code}: ${stderr.trim()}`));
-            }
-        });
+// Sync execFileSync, NOT async execFile/spawn. In a Finder-launched packaged
+// .app the async ChildProcess.spawn path fails with `spawn EBADF` (errno -9)
+// every detector tick. The synchronous path avoids it and is already proven
+// in this exact packaged app -- main.ts uses execFileSync at startup.
+function runPmsetAssertions(): string {
+    return execFileSync("/usr/bin/pmset", ["-g", "assertions"], {
+        timeout: PMSET_TIMEOUT_MS,
+        encoding: "utf8",
+        stdio: ["ignore", "pipe", "ignore"],
+        windowsHide: true,
     });
 }
 
@@ -84,21 +22,15 @@ export class MacOsMicProbe implements MicProbe {
     async probe(): Promise<MicUser[]> {
         let stdout: string;
         try {
-            stdout = await runPmsetAssertions();
+            stdout = runPmsetAssertions();
         } catch (err) {
             console.error("[MeetingDetect] macOS probe failed:", err);
             return [];
         }
-
         return parseAssertions(stdout);
     }
 }
 
-/**
- * Parse `pmset -g assertions` stdout into the distinct processes holding a
- * meeting-relevant assertion. Pure (no OS calls) so it's unit-testable against
- * captured pmset output. One entry per pid; the first matching line wins.
- */
 export function parseAssertions(stdout: string): MicUser[] {
     const seen = new Map<number, MicUser>();
     for (const line of stdout.split("\n")) {