diff --git a/src/main/codex-accounts/runtime-home-service.test.ts b/src/main/codex-accounts/runtime-home-service.test.ts
index f4349930751..b3f9fa4f41f 100644
--- a/src/main/codex-accounts/runtime-home-service.test.ts
+++ b/src/main/codex-accounts/runtime-home-service.test.ts
@@ -361,6 +361,48 @@ describe('CodexRuntimeHomeService', () => {
     )
   })
 
+  it('uses the canonical Electron userData for legacy active host migration', async () => {
+    const staleUserDataDir = mkdtempSync(join(tmpdir(), 'orca-stale-runtime-home-'))
+    const staleRuntimeHomePath = join(staleUserDataDir, 'codex-runtime-home', 'home')
+    try {
+      mkdirSync(staleRuntimeHomePath, { recursive: true })
+      process.env.ORCA_USER_DATA_PATH = staleUserDataDir
+      const legacyLaunchHomePath = join(
+        testState.userDataDir,
+        'codex-runtime-home',
+        'launch',
+        'host',
+        'account-old',
+        'home'
+      )
+      const legacyActiveHomePath = getLegacyActiveHostCodexHomePath()
+      mkdirSync(legacyLaunchHomePath, { recursive: true })
+      mkdirSync(join(legacyActiveHomePath, '..'), { recursive: true })
+      symlinkSync(
+        legacyLaunchHomePath,
+        legacyActiveHomePath,
+        process.platform === 'win32' ? 'junction' : undefined
+      )
+      writeFileSync(getSystemCodexAuthPath(), '{"account":"system"}\n', 'utf-8')
+      const store = createStore(createSettings())
+
+      const { configureOrcaUserDataPathEnv } = await import('../startup/configure-process')
+      configureOrcaUserDataPathEnv()
+      const { CodexRuntimeHomeService } = await import('./runtime-home-service')
+      new CodexRuntimeHomeService(store as never)
+
+      expect(process.env.ORCA_USER_DATA_PATH).toBe(testState.userDataDir)
+      expect(normalizeLinkTarget(readlinkSync(legacyActiveHomePath))).toBe(
+        normalizeLinkTarget(getRuntimeCodexHomePath())
+      )
+      expect(normalizeLinkTarget(readlinkSync(legacyActiveHomePath))).not.toBe(
+        normalizeLinkTarget(staleRuntimeHomePath)
+      )
+    } finally {
+      rmSync(staleUserDataDir, { recursive: true, force: true })
+    }
+  })
+
   it('does not create a legacy active host pointer for fresh shared-home users', async () => {
     writeFileSync(getSystemCodexAuthPath(), '{"account":"system"}\n', 'utf-8')
     const store = createStore(createSettings())
diff --git a/src/main/index.ts b/src/main/index.ts
index fa90ae9fb10..71e9fc3c09d 100644
--- a/src/main/index.ts
+++ b/src/main/index.ts
@@ -45,6 +45,7 @@ import {
 import { checkForUpdatesFromMenu, isQuittingForUpdate } from './updater'
 import {
   configureDevUserDataPath,
+  configureOrcaUserDataPathEnv,
   enableMainProcessGpuFeatures,
   installDevParentDisconnectQuit,
   installDevParentSignalQuit,
@@ -233,9 +234,7 @@ if (app.isPackaged && process.platform !== 'win32') {
   })
 }
 configureDevUserDataPath(is.dev)
-// Why: CLI-shared Codex helpers cannot import Electron. Seed the resolved
-// app userData path once Electron has applied dev/e2e overrides.
-process.env.ORCA_USER_DATA_PATH ??= app.getPath('userData')
+configureOrcaUserDataPathEnv()
 const startupDiagnosticsEnabled = isStartupDiagnosticsEnabled()
 if (startupDiagnosticsEnabled) {
   logStartupDiagnostic('before-single-instance-lock', {
diff --git a/src/main/startup/configure-process.test.ts b/src/main/startup/configure-process.test.ts
index 4f33ea01809..370b1d3bdb8 100644
--- a/src/main/startup/configure-process.test.ts
+++ b/src/main/startup/configure-process.test.ts
@@ -151,6 +151,30 @@ describe('configureDevUserDataPath', () => {
   })
 })
 
+describe('configureOrcaUserDataPathEnv', () => {
+  it('overwrites stale inherited ORCA_USER_DATA_PATH with Electron userData', async () => {
+    const { app } = await import('electron')
+    const { configureOrcaUserDataPathEnv } = await import('./configure-process')
+    const originalUserDataPath = process.env.ORCA_USER_DATA_PATH
+    process.env.ORCA_USER_DATA_PATH = '/tmp/stale-orca-user-data'
+    app.setPath('userData', '/tmp/current-orca-user-data')
+    let configuredUserDataPath: string | undefined
+
+    try {
+      configureOrcaUserDataPathEnv()
+      configuredUserDataPath = process.env.ORCA_USER_DATA_PATH
+    } finally {
+      if (originalUserDataPath === undefined) {
+        delete process.env.ORCA_USER_DATA_PATH
+      } else {
+        process.env.ORCA_USER_DATA_PATH = originalUserDataPath
+      }
+    }
+
+    expect(configuredUserDataPath).toBe('/tmp/current-orca-user-data')
+  })
+})
+
 describe('shouldInstallManagedHooks', () => {
   it('keeps managed hook auto-install enabled for default dev runs', async () => {
     const { shouldInstallManagedHooks } = await import('./configure-process')
diff --git a/src/main/startup/configure-process.ts b/src/main/startup/configure-process.ts
index 175cfab544e..4a859d64597 100644
--- a/src/main/startup/configure-process.ts
+++ b/src/main/startup/configure-process.ts
@@ -145,6 +145,13 @@ export function configureDevUserDataPath(isDev: boolean): void {
   app.setPath('userData', join(app.getPath('appData'), 'orca-dev'))
 }
 
+export function configureOrcaUserDataPathEnv(): void {
+  // Why: app relaunches can inherit an ORCA_USER_DATA_PATH from an older CLI or
+  // updater process. Main must canonicalize it before CLI-shared modules build
+  // runtime-home paths, or migrations can bridge two Orca app-data directories.
+  process.env.ORCA_USER_DATA_PATH = app.getPath('userData')
+}
+
 export function shouldInstallManagedHooks(isDev: boolean): boolean {
   void isDev
   // Why: managed hook installation now targets Orca-owned, environment-scoped