diff --git a/src/main/index.ts b/src/main/index.ts
index 7bb8487d4..481eb6885 100644
--- a/src/main/index.ts
+++ b/src/main/index.ts
@@ -90,6 +90,7 @@ import { secureWindow } from './security'
 import { SafeModeFrame } from './safe-mode-frame'
 import { desktopResourceUrl, installDesktopProtocol, registerDesktopScheme, SAFE_MODE_PAGE } from './desktop-protocol'
 import { ensureLaunchRoot } from './state/launch-root'
+import { initializeDesktopInstall } from './state/desktop-startup-install'
 import {
   listInstalledProfilePlugins,
   pruneUnresolvableProfileBundles,
@@ -3557,7 +3558,13 @@ if (isDaemonLaunch(process.env, process.platform)) {
     // and the splash instead of blocking the main process right before the
     // Harness spawn. Only the instance that will actually launch pays for it.
     void prewarmShellEnvironment()
-    initializeDesktopService()
+    // Classify before DesktopService creates installation.json and bootstrap
+    // creates launch-root; either path would otherwise look like legacy data.
+    initializeDesktopInstall({
+      userDataPath: app.getPath('userData'),
+      appVersion: app.getVersion(),
+      developmentBuild
+    }, initializeDesktopService)
     app.on('second-instance', (_event, argv) => {
       if (!isUserInitiatedInstance(argv)) return
       if (shouldStartInSafeMode(argv)) {
diff --git a/src/main/state/desktop-startup-install.ts b/src/main/state/desktop-startup-install.ts
new file mode 100644
index 000000000..c1638d2cb
--- /dev/null
+++ b/src/main/state/desktop-startup-install.ts
@@ -0,0 +1,10 @@
+import { classifyDesktopInstall, type ClassifyDesktopInstallOptions } from './desktop-install-state'
+
+/** Persist the first-install decision before startup services create legacy evidence. */
+export function initializeDesktopInstall(
+  options: ClassifyDesktopInstallOptions,
+  initializeService: () => void
+): void {
+  classifyDesktopInstall(options)
+  initializeService()
+}
diff --git a/test/desktop-startup-install.test.ts b/test/desktop-startup-install.test.ts
new file mode 100644
index 000000000..1be80a939
--- /dev/null
+++ b/test/desktop-startup-install.test.ts
@@ -0,0 +1,53 @@
+import { mkdir, mkdtemp, readFile, rm } from 'node:fs/promises'
+import { mkdirSync, readFileSync, writeFileSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, describe, expect, it } from 'vitest'
+import { initializeDesktopInstall } from '../src/main/state/desktop-startup-install'
+import { desktopInstallStatePath } from '../src/main/state/desktop-install-state'
+
+const roots: string[] = []
+
+async function userData(): Promise<string> {
+  const root = await mkdtemp(join(tmpdir(), 'dsh-startup-install-'))
+  roots.push(root)
+  return root
+}
+
+afterEach(async () => {
+  await Promise.all(roots.splice(0).map(root => rm(root, { recursive: true, force: true })))
+})
+
+describe('desktop startup install classification', () => {
+  it('persists a new install before the desktop service creates legacy evidence', async () => {
+    const root = await userData()
+    let classificationAtServiceStart: string | undefined
+    initializeDesktopInstall({
+      userDataPath: root,
+      appVersion: '0.11.0',
+      developmentBuild: false
+    }, () => {
+      classificationAtServiceStart = JSON.parse(
+        // The real DesktopService creates installation.json at this point.
+        readFileSync(desktopInstallStatePath(join(root, 'harness')), 'utf8')
+      ).classification
+      mkdirSync(join(root, 'desktop-service'), { recursive: true })
+      writeFileSync(join(root, 'desktop-service', 'installation.json'), '{}')
+    })
+
+    expect(classificationAtServiceStart).toBe('new')
+    expect(JSON.parse(await readFile(desktopInstallStatePath(join(root, 'harness')), 'utf8')).classification).toBe('new')
+  })
+
+  it('keeps an existing install ineligible when the service starts', async () => {
+    const root = await userData()
+    await mkdir(join(root, 'launch-root'))
+    let classificationAtServiceStart: string | undefined
+    initializeDesktopInstall({ userDataPath: root, appVersion: '0.11.0', developmentBuild: false }, () => {
+      classificationAtServiceStart = readFileSync(
+        desktopInstallStatePath(join(root, 'harness')), 'utf8'
+      )
+    })
+    expect(JSON.parse(classificationAtServiceStart ?? '').classification).toBe('existing')
+  })
+})