diff --git a/src/main/daemon/daemon-child-exit-observer.test.ts b/src/main/daemon/daemon-child-exit-observer.test.ts
index 1cd394131c9..20149348fcc 100644
--- a/src/main/daemon/daemon-child-exit-observer.test.ts
+++ b/src/main/daemon/daemon-child-exit-observer.test.ts
@@ -44,6 +44,20 @@ describe('observeDaemonChildExit', () => {
     observer.stop()
   })
 
+  it('retains fatal stderr that arrives before the independent ready IPC callback', () => {
+    const child = createChild()
+    const onExit = vi.fn()
+    const observer = observeDaemonChildExit(child, onExit)
+
+    child.stderr.write('FATAL ERROR before ready dispatch')
+    observer.markReady()
+    child.emit('close', 134, null)
+
+    expect(onExit).toHaveBeenCalledWith(
+      expect.objectContaining({ stderrTail: 'FATAL ERROR before ready dispatch' })
+    )
+  })
+
   it('stops observing and destroys the startup pipe on launch failure', () => {
     const child = createChild()
     const destroy = vi.spyOn(child.stderr, 'destroy')
diff --git a/src/main/daemon/daemon-child-exit-observer.ts b/src/main/daemon/daemon-child-exit-observer.ts
index 94d9101884b..2af959ec425 100644
--- a/src/main/daemon/daemon-child-exit-observer.ts
+++ b/src/main/daemon/daemon-child-exit-observer.ts
@@ -72,7 +72,6 @@ export function observeDaemonChildExit(
         return
       }
       ready = true
-      stderrTail = Buffer.alloc(0)
       child.stderr?.on('error', onStderrError)
       child.stderr?.unref?.()
       child.on('close', onClose)