diff --git a/apps/bootstrap-installer/src-tauri/src/bootstrap.rs b/apps/bootstrap-installer/src-tauri/src/bootstrap.rs
index 783916cd74..8d6d81cb56 100644
--- a/apps/bootstrap-installer/src-tauri/src/bootstrap.rs
+++ b/apps/bootstrap-installer/src-tauri/src/bootstrap.rs
@@ -583,7 +583,7 @@ async fn run_bootstrap(
         let err = format!(
             "install.ps1 -Manifest failed: exit {:?}\n{}",
             manifest_result.exit_code,
-            manifest_result.stderr.trim()
+            crate::events::strip_ansi(manifest_result.stderr.trim())
         );
         emit_event(
             &app,
diff --git a/apps/desktop/electron/bootstrap-runner.test.ts b/apps/desktop/electron/bootstrap-runner.test.ts
index 19fb679fd8..5cc6f92f23 100644
--- a/apps/desktop/electron/bootstrap-runner.test.ts
+++ b/apps/desktop/electron/bootstrap-runner.test.ts
@@ -289,3 +289,27 @@ test('installer log lines reach the emitter without escape sequences; \\r redraw
   // Plain multi-byte text is untouched.
   assert.equal(cleanInstallerLogLine('Ready — café ✓ 中文'), 'Ready — café ✓ 中文')
 })
+
+test.skipIf(process.platform === 'win32')(
+  'a manifest-step failure surfaces the installer tail without escape sequences',
+  async () => {
+    const home = mkTmpHome()
+    fs.mkdirSync(path.join(home, 'scripts'))
+    fs.writeFileSync(
+      path.join(home, 'scripts', 'install.sh'),
+      '#!/usr/bin/env bash\nprintf "\\033[0;31m\\xe2\\x9c\\x97\\033[0m manifest broke\\n" >&2\nexit 3\n'
+    )
+
+    const result = await runBootstrap({
+      installStamp: null,
+      activeRoot: home,
+      sourceRepoRoot: home,
+      hermesHome: home,
+      logRoot: home,
+      onEvent: () => {}
+    })
+
+    assert.equal(result.ok, false)
+    assert.equal(result.error, 'install.sh --manifest failed: exit 3\n✗ manifest broke')
+  }
+)
diff --git a/apps/desktop/electron/bootstrap-runner.ts b/apps/desktop/electron/bootstrap-runner.ts
index dce1713a5f..90b3f55731 100644
--- a/apps/desktop/electron/bootstrap-runner.ts
+++ b/apps/desktop/electron/bootstrap-runner.ts
@@ -737,9 +737,11 @@ async function fetchManifest({
   })
 
   if (result.code !== 0) {
-    throw new Error(
-      `${isPosix ? 'install.sh --manifest' : 'install.ps1 -Manifest'} failed: exit ${result.code}\n${result.stderr || result.stdout}`
-    )
+    // The tail lands in the Setup failure banner, not the log ring, so strip
+    // the installer's colour/OSC bytes here too (#112675).
+    const tail = stripAnsi(result.stderr || result.stdout).trim()
+
+    throw new Error(`${isPosix ? 'install.sh --manifest' : 'install.ps1 -Manifest'} failed: exit ${result.code}\n${tail}`)
   }
 
   // The manifest is the LAST JSON line on stdout (install.ps1 may print