diff --git a/.github/workflows/windows-free-tests.yml b/.github/workflows/windows-free-tests.yml
index c05a7d002..7435814cc 100644
--- a/.github/workflows/windows-free-tests.yml
+++ b/.github/workflows/windows-free-tests.yml
@@ -111,6 +111,8 @@ jobs:
             browse/test/claude-bin.test.ts \
             test/test-free-shards.test.ts \
             browse/test/file-permissions.test.ts \
+            browse/test/bun-polyfill.test.ts \
+            browse/test/windows-spawn-hide.test.ts \
             browse/test/security.test.ts \
             browse/test/server-sanitize-surrogates.test.ts \
             test/setup-windows-fallback.test.ts \
diff --git a/browse/src/cli.ts b/browse/src/cli.ts
index 213471f54..ed6703901 100644
--- a/browse/src/cli.ts
+++ b/browse/src/cli.ts
@@ -143,7 +143,7 @@ async function killServer(pid: number): Promise<void> {
     try {
       Bun.spawnSync(
         ['taskkill', '/PID', String(pid), '/T', '/F'],
-        { stdout: 'pipe', stderr: 'pipe', timeout: 5000 }
+        { stdout: 'pipe', stderr: 'pipe', timeout: 5000, windowsHide: true }
       );
     } catch (err: any) {
       if (err?.code !== 'ENOENT') throw err;
@@ -323,9 +323,9 @@ async function startServer(extraEnv?: Record<string, string>): Promise<ServerSta
     const launcherCode =
       `const{spawn}=require('child_process');` +
       `spawn(process.execPath,[${JSON.stringify(NODE_SERVER_SCRIPT)}],` +
-      `{detached:true,stdio:['ignore','ignore','ignore'],env:Object.assign({},process.env,` +
+      `{detached:true,windowsHide:true,stdio:['ignore','ignore','ignore'],env:Object.assign({},process.env,` +
       `${extraEnvStr})}).unref()`;
-    Bun.spawnSync(['node', '-e', launcherCode], { stdio: ['ignore', 'ignore', 'ignore'] });
+    Bun.spawnSync(['node', '-e', launcherCode], { stdio: ['ignore', 'ignore', 'ignore'], windowsHide: true });
   } else {
     // macOS/Linux: Bun.spawn().unref() only removes the child from Bun's event
     // loop — it does NOT call setsid(), so the spawned server stays in the
@@ -340,6 +340,7 @@ async function startServer(extraEnv?: Record<string, string>): Promise<ServerSta
     // the Windows path's rationale — same root cause, different OS API.
     nodeSpawn('bun', ['run', SERVER_SCRIPT], {
       detached: true,
+      windowsHide: true,
       stdio: ['ignore', 'ignore', 'ignore'],
       env: { ...process.env, BROWSE_STATE_FILE: config.stateFile, BROWSE_PARENT_PID: parentPid, ...extraEnv },
     }).unref();
diff --git a/browse/src/cookie-import-browser.ts b/browse/src/cookie-import-browser.ts
index 66328432a..19daa196b 100644
--- a/browse/src/cookie-import-browser.ts
+++ b/browse/src/cookie-import-browser.ts
@@ -526,6 +526,7 @@ async function dpapiDecrypt(encryptedBytes: Buffer): Promise<Buffer> {
   ].join('; ');
 
   const proc = Bun.spawn(['powershell', '-NoProfile', '-Command', script], {
+    windowsHide: true,
     stdin: 'pipe',
     stdout: 'pipe',
     stderr: 'pipe',
@@ -778,7 +779,7 @@ function isBrowserRunning(browserName: string): Promise<boolean> {
   const exe = browserName.toLowerCase().includes('edge') ? 'msedge.exe' : 'chrome.exe';
   return new Promise((resolve) => {
     const proc = Bun.spawn(['tasklist', '/FI', `IMAGENAME eq ${exe}`, '/NH'], {
-      stdout: 'pipe', stderr: 'pipe',
+      stdout: 'pipe', stderr: 'pipe', windowsHide: true,
     });
     proc.exited.then(async () => {
       const out = await new Response(proc.stdout).text();
diff --git a/browse/src/error-handling.ts b/browse/src/error-handling.ts
index 2c4e271e8..3be921fa2 100644
--- a/browse/src/error-handling.ts
+++ b/browse/src/error-handling.ts
@@ -42,7 +42,7 @@ export function isProcessAlive(pid: number): boolean {
     try {
       const result = Bun.spawnSync(
         ['tasklist', '/FI', `PID eq ${pid}`, '/NH', '/FO', 'CSV'],
-        { stdout: 'pipe', stderr: 'pipe', timeout: 3000 }
+        { stdout: 'pipe', stderr: 'pipe', timeout: 3000, windowsHide: true }
       );
       return result.stdout.toString().includes(`"${pid}"`);
     } catch {