diff --git a/src/main/orcad/orcad-command-arguments.ts b/src/main/orcad/orcad-command-arguments.ts
index ad4423f844c..51431de4d74 100644
--- a/src/main/orcad/orcad-command-arguments.ts
+++ b/src/main/orcad/orcad-command-arguments.ts
@@ -1,4 +1,4 @@
-import type { OrcadOptions } from './orcad-entry'
+import type { OrcadOptions } from './orcad-start-contract'
 import { DEFAULT_WS_PORT } from '../runtime/runtime-rpc/runtime-rpc-pairing-types'
 import { ORCAD_LOOPBACK_BIND_HOST } from './orcad-bind-address'
 import { getServeOptionValidationError } from '../../shared/serve-option-validation'
diff --git a/src/main/orcad/orcad-duplicate-pty-repair-startup.test.ts b/src/main/orcad/orcad-duplicate-pty-repair-startup.test.ts
new file mode 100644
index 00000000000..74eed4fd84e
--- /dev/null
+++ b/src/main/orcad/orcad-duplicate-pty-repair-startup.test.ts
@@ -0,0 +1,306 @@
+import { mkdtempSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, beforeEach, expect, it, vi, type Mock } from 'vitest'
+import { getDefaultWorkspaceSession } from '../../shared/constants'
+import type { PersistedState } from '../../shared/persisted-state-types'
+import { agentHookServer } from '../agent-hooks/server'
+import { ProfileStateSqliteAuthority } from '../persistence/profile-state/profile-state-sqlite-authority'
+import {
+  emptyTerminalSessionProfile,
+  FIXTURE_GIT_WORKTREE_ID,
+  openTopologyStore
+} from '../persistence/terminal-topology/terminal-topology-profile-fixture'
+import { DelayedAuthority } from '../persistence/loading-store/profile-state-delayed-authority-fixture'
+import { Store } from '../persistence/loading-store/store'
+import {
+  leafIds,
+  WindowSession
+} from '../persistence/terminal-topology/terminal-topology-window-session-fixture'
+
+const state = vi.hoisted(() => {
+  const value: {
+    root: string
+    store: Store | null
+    layoutOwnerIsMain: boolean
+    rekeyWorkerTerminalResourcePaneKey: Mock<() => number>
+    /** What a startup step saw on disk; set by a test that watches the order. */
+    onStartupStep: ((step: string) => void) | null
+  } = {
+    root: '',
+    store: null,
+    layoutOwnerIsMain: true,
+    rekeyWorkerTerminalResourcePaneKey: vi.fn(() => 1),
+    onStartupStep: null
+  }
+  return value
+})
+
+vi.mock('../../shared/layout-owner-switch', () => ({
+  get ORCA_LAYOUT_OWNER_IS_MAIN() {
+    return state.layoutOwnerIsMain
+  }
+}))
+vi.mock('../telemetry/client', () => ({ track: vi.fn() }))
+// Why: startup reconciles the user-global agent configs; keep it off this machine's real home.
+vi.mock('../codex/codex-hook-reconcile', async (importOriginal) => ({
+  ...(await importOriginal<Record<string, unknown>>()),
+  startCodexHooks: vi.fn()
+}))
+vi.mock('../agent-hooks/managed-agent-hook-controls', async (importOriginal) => ({
+  ...(await importOriginal<Record<string, unknown>>()),
+  installManagedAgentHooks: vi.fn(async () => [])
+}))
+vi.mock('../agent-hooks/local-agent-cli-presence', async (importOriginal) => ({
+  ...(await importOriginal<Record<string, unknown>>()),
+  hydrateAgentCliShellPath: async () => {}
+}))
+vi.mock('../agent-hooks/agent-home-login-shell', () => ({
+  adoptLoginShellAgentHomes: async () => {}
+}))
+vi.mock('../opencode/opencode-status-plugin-startup-refresh', () => ({
+  refreshInstalledOpenCodeStatusPlugins: vi.fn()
+}))
+vi.mock('./orcad-app-paths', () => ({
+  resolveOrcadInstallRoot: () => state.root,
+  resolveOrcadPath: () => state.root,
+  resolveUserDataPath: () => state.root
+}))
+vi.mock('./orcad-plaintext-credential-migration', () => ({
+  orcadCredentialRoot: () => state.root,
+  migratePlaintextCredentials: () => ({ sealed: 0, failed: 0 })
+}))
+vi.mock('./orcad-account-services', () => ({ createOrcadAccountServices: () => null }))
+vi.mock('./orcad-browser-provider', () => ({ resolveOrcadBrowserProvider: async () => null }))
+vi.mock('./orcad-instance-lock', () => ({
+  acquireOrcadInstanceLock: () => ({
+    path: join(state.root, 'orcad.lock'),
+    record: { pid: process.pid, startedAtMs: null, nonce: 'repair-instance' },
+    release() {}
+  })
+}))
+vi.mock('./orcad-daemon-supervision', () => ({
+  startOrcadDaemon: async () => {},
+  stopOrcadDaemon: async () => {}
+}))
+vi.mock('./orcad-health', () => ({ collectOrcadHealth: async () => ({}) }))
+vi.mock('./orcad-automations', () => ({
+  startOrcadAutomations: () => {},
+  stopOrcadAutomationScheduler: () => {},
+  orcadAutomationsKeepHostBusy: () => false
+}))
+vi.mock('../runtime/agent-state-rules/agent-state-rules-live-update', () => ({
+  startAgentStateRulesLiveUpdates: () => {}
+}))
+vi.mock('../daemon/daemon-provider-state', () => ({ daemonOwnsFreshPersistentPtys: () => false }))
+vi.mock('../ipc/pty/register-headless-runtime', () => ({
+  registerHeadlessPtyRuntime: async () => {}
+}))
+vi.mock('../ipc/pty/provider/registry', () => ({ getLocalPtyProvider: () => null }))
+// The real Store orcad loads, on a profile holding one terminal drawn in two panes.
+vi.mock('./orcad-profile-state-startup', () => ({
+  createOrcadProfileStateStartup: async () => ({
+    store: state.store,
+    authority: {
+      backend: 'sqlite',
+      classification: 'neither',
+      authority_mode: 'sqlite-candidate',
+      runtime: 'orcad',
+      migrated: false
+    }
+  })
+}))
+vi.mock('../orca-profiles/profile-index-store', () => ({
+  initOrcaProfilePaths() {},
+  ensureActiveOrcaProfile: () => ({
+    dataFile: join(state.root, 'profile.json'),
+    stateDatabaseFile: join(state.root, 'profile-state.db'),
+    profile: { id: 'repair-profile' }
+  })
+}))
+vi.mock('../ssh/ssh-host-key-store', () => ({ initSshHostKeyStoreFile() {} }))
+vi.mock('../server/serve-readiness', () => ({
+  ServeReadinessPublisher: class {
+    async publish() {}
+  }
+}))
+vi.mock('../runtime/push/desktop-push-service', () => ({
+  DesktopPushService: { create: () => null }
+}))
+vi.mock('../runtime/orca-runtime', () => ({
+  OrcaRuntimeService: class {
+    readonly sidebarFacts = null
+    getRuntimeId() {
+      return 'repair-runtime'
+    }
+    getExistingOrchestrationDb() {
+      return { rekeyWorkerTerminalResourcePaneKey: state.rekeyWorkerTerminalResourcePaneKey }
+    }
+    rehydrateClientHostedBrowserPages() {}
+    restoreHostAccountLaunchEnv() {}
+    async refreshRestoredOrchestrationAuthority() {}
+    async reconcileLegacyWorkerTerminals() {
+      state.onStartupStep?.('reconcile')
+    }
+    async installPendingOrcadMigrationShellHistory() {}
+    async stopLegacyWorkerTerminalRecovery() {}
+    async closeNotificationDismissals() {}
+    syncWindowGraph() {}
+  }
+}))
+vi.mock('../runtime/runtime-rpc', () => ({
+  OrcaRuntimeRpcServer: class {
+    async start() {
+      state.onStartupStep?.('rpc.start')
+    }
+    async stop() {}
+    getWebSocketEndpoint() {
+      return null
+    }
+  }
+}))
+
+const TAB = 'tab-1'
+const KEPT = '11111111-1111-4111-8111-111111111111'
+const DUPLICATE = '22222222-2222-4222-8222-222222222222'
+const directories: string[] = []
+
+beforeEach(() => {
+  // startOrcad canonicalizes this; stubbing restores the prior value after each test.
+  vi.stubEnv('ORCA_USER_DATA_PATH', '')
+})
+
+afterEach(() => {
+  state.layoutOwnerIsMain = true
+  state.onStartupStep = null
+  state.rekeyWorkerTerminalResourcePaneKey.mockClear()
+  vi.unstubAllEnvs()
+  vi.restoreAllMocks()
+  for (const directory of directories.splice(0)) {
+    rmSync(directory, { recursive: true, force: true })
+  }
+})
+
+function temporaryDirectory(prefix: string): string {
+  const directory = mkdtempSync(join(tmpdir(), prefix))
+  directories.push(directory)
+  return directory
+}
+
+/** The stored shape a window save leaves behind: one terminal drawn in two panes of one tab. */
+function duplicatePtyProfile(): string {
+  const window = new WindowSession(getDefaultWorkspaceSession())
+  window.addTab(FIXTURE_GIT_WORKTREE_ID, TAB, KEPT)
+  window.setLayout(
+    TAB,
+    {
+      type: 'split',
+      direction: 'vertical',
+      first: { type: 'leaf', leafId: KEPT },
+      second: { type: 'leaf', leafId: DUPLICATE }
+    },
+    { [KEPT]: 'pty-1', [DUPLICATE]: 'pty-1' }
+  )
+  return JSON.stringify({
+    ...JSON.parse(emptyTerminalSessionProfile()),
+    workspaceSession: window.session
+  })
+}
+
+function storedLeafIds(directory: string): string[] {
+  const reader = new ProfileStateSqliteAuthority(join(directory, 'profile-state.db'), 'topology')
+  try {
+    // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: the test wrote this profile as PersistedState.
+    const stored = JSON.parse(reader.readSerializedState() ?? '{}') as PersistedState
+    return leafIds(stored.workspaceSession?.terminalLayoutsByTabId?.[TAB]?.root)
+  } finally {
+    reader.close()
+  }
+}
+
+async function seedDuplicatePtyProfile(): Promise<string> {
+  state.root = temporaryDirectory('orcad-duplicate-pty-repair-')
+  const profileDirectory = temporaryDirectory('orcad-duplicate-pty-profile-')
+  state.store = await openTopologyStore(profileDirectory, duplicatePtyProfile())
+  return profileDirectory
+}
+
+it('repairs a stored duplicate-terminal pane at orcad startup, moving owners before the write', async () => {
+  const profileDirectory = await seedDuplicatePtyProfile()
+  const diskAtTransfer: string[][] = []
+  const transfer = vi
+    .spyOn(agentHookServer, 'transferPaneAuthority')
+    .mockImplementation(() => diskAtTransfer.push(storedLeafIds(profileDirectory)))
+
+  const { startOrcad } = await import('./orcad-entry')
+  const host = await startOrcad({ noPairing: true, json: true })
+  try {
+    await vi.waitFor(() => expect(storedLeafIds(profileDirectory)).toEqual([KEPT]))
+    expect(transfer).toHaveBeenCalledExactlyOnceWith(
+      `${TAB}:${DUPLICATE}`,
+      `${TAB}:${KEPT}`,
+      'pty-1',
+      expect.any(Number),
+      { authorityVerified: true }
+    )
+    expect(state.rekeyWorkerTerminalResourcePaneKey).toHaveBeenCalledExactlyOnceWith({
+      fromPaneKey: `${TAB}:${DUPLICATE}`,
+      toPaneKey: `${TAB}:${KEPT}`
+    })
+    // The status moved while disk still held both panes.
+    expect(diskAtTransfer).toEqual([[KEPT, DUPLICATE]])
+  } finally {
+    await host.stop()
+  }
+})
+
+it('leaves the stored panes alone when the build keeps the window as layout owner', async () => {
+  state.layoutOwnerIsMain = false
+  const profileDirectory = await seedDuplicatePtyProfile()
+  const transfer = vi.spyOn(agentHookServer, 'transferPaneAuthority')
+
+  const { startOrcad } = await import('./orcad-entry')
+  const host = await startOrcad({ noPairing: true, json: true })
+  await host.stop()
+
+  expect(transfer).not.toHaveBeenCalled()
+  expect(state.rekeyWorkerTerminalResourcePaneKey).not.toHaveBeenCalled()
+  expect(storedLeafIds(profileDirectory)).toEqual([KEPT, DUPLICATE])
+})
+
+it('writes the repair before reconcile and RPC even when a profile write is in flight', async () => {
+  state.root = temporaryDirectory('orcad-duplicate-pty-repair-')
+  const profileDirectory = temporaryDirectory('orcad-duplicate-pty-profile-')
+  const inner = new ProfileStateSqliteAuthority(
+    join(profileDirectory, 'profile-state.db'),
+    'topology'
+  )
+  inner.writeSerializedState(Buffer.from(duplicatePtyProfile()))
+  const authority = new DelayedAuthority(inner)
+  const store = new Store({
+    dataFile: join(profileDirectory, 'orca-data.json'),
+    profileStateAuthority: authority
+  })
+  await store.flushPendingOrThrowAsync()
+  state.store = store
+  vi.spyOn(agentHookServer, 'transferPaneAuthority').mockImplementation(() => {})
+  const diskAtStep: Record<string, string[]> = {}
+  state.onStartupStep = (step) => (diskAtStep[step] = storedLeafIds(profileDirectory))
+
+  // An earlier profile write is still in flight; the repair queues behind it.
+  const held = authority.pause()
+  store.updateSettings({ agentStatusHooksEnabled: false })
+  const heldWrite = store.flushPendingOrThrowAsync()
+  await held.started.promise
+  const { startOrcad } = await import('./orcad-entry')
+  const startup = startOrcad({ noPairing: true, json: true })
+  await new Promise((resolve) => setTimeout(resolve, 200))
+  held.finish.resolve()
+  await heldWrite
+  const host = await startup
+  try {
+    expect(diskAtStep).toEqual({ reconcile: [KEPT], 'rpc.start': [KEPT] })
+  } finally {
+    await host.stop()
+  }
+})
diff --git a/src/main/orcad/orcad-entry.ts b/src/main/orcad/orcad-entry.ts
index 8e46f80140e..4f449e5b252 100644
--- a/src/main/orcad/orcad-entry.ts
+++ b/src/main/orcad/orcad-entry.ts
@@ -13,7 +13,6 @@
 import { join } from 'node:path'
 import process from 'node:process'
 import { getAppEnvironment } from '../../shared/app-environment'
-import type { ServeReadiness } from '../server/serve-readiness'
 import { resolveOrcadInstallRoot, resolveUserDataPath } from './orcad-app-paths'
 import { prepareOrcadCliLauncher } from './orcad-cli-launcher'
 import {
@@ -32,7 +31,7 @@ import { ORCAD_USAGE, parseArgs, resolveOrcadWebClientRoot } from './orcad-comma
 import type { OrcadRuntimeCleanup } from './orcad-runtime-lifetime'
 import { installOrcadStopRequestListeners } from './orcad-stop-request-listener'
 import { prepareOrcadManagedStop } from './orcad-managed-stop-admission'
-import type { OrcadManagedStopContext } from '../../shared/orcad-stop-request'
+import type { OrcadHandle, OrcadOptions } from './orcad-start-contract'
 import { beginOrcadIdleExit, bindOrcadIdleShutdown } from './orcad-managed-idle-exit-host'
 import { orcadAutomationsKeepHostBusy, startOrcadAutomations } from './orcad-automations'
 import {
@@ -43,36 +42,12 @@ import { stampRuntimeSourceEnv } from '../../shared/runtime-source-env'
 import { adoptWslHostLoginEnvironment } from './orcad-wsl-host-login-environment'
 import { installOrcadProcessErrorGuards } from './orcad-process-error-guards'
 import { orcadWsPortOptions } from './orcad-ws-port-policy'
+import { ORCA_LAYOUT_OWNER_IS_MAIN } from '../../shared/layout-owner-switch'
 
 export { parseArgs }
 
 let closeOrcadObservability = (): void => {}
 
-export type OrcadOptions = {
-  port?: number
-  json?: boolean
-  noPairing?: boolean
-  pairingAddress?: string
-  /** Desktop `orca serve` parity: a mobile-scoped offer with a terminal QR. */
-  mobilePairing?: boolean
-  /** Lets the paired runtime client drive this machine's desktop (computer.*). */
-  grantDesktopControl?: boolean
-  /** Desktop `orca serve` parity: print only the ephemeral-VM recipe line. */
-  recipeJson?: boolean
-  projectRoot?: string
-  /** Literal IP to bind. Defaults to loopback; see orcad-bind-address.ts. */
-  bind?: string
-  /** The browser client's directory; the slot carries none, so `orca serve` passes the app's. */
-  webClientRoot?: string
-}
-
-export type OrcadHandle = {
-  readiness: ServeReadiness
-  /** What an instance-bound stop request must name to stop this process. */
-  managedStop: OrcadManagedStopContext
-  stop(): Promise<void>
-}
-
 /**
  * Boot the runtime and serve RPC. Resolves once the transport is listening and the
  * readiness payload has been published, mirroring the desktop `--serve` contract byte
@@ -289,6 +264,12 @@ async function startOrcadRuntime(
   startAgentStateRulesLiveUpdates(profileStore, (rules) =>
     console.info(`[orcad] agent state rules ${rules.version} (${rules.source})`)
   )
+  // Switch point: main's load repair, here too, now that this runtime can move pane owners.
+  if (ORCA_LAYOUT_OWNER_IS_MAIN) {
+    const { repairDuplicatePtyPanesOnStart } = await import('../runtime/moved-pane-owner-rekey')
+    // Awaited: it queues behind any in-flight write, and must land before reconcile and RPC.
+    await repairDuplicatePtyPanesOnStart(profileStore, runtime)
+  }
 
   // Why here too and not only on the desktop: nothing else republishes `session.tabs` when a
   // pane's status row changes, and orcad's whole job is serving paired clients.
diff --git a/src/main/orcad/orcad-serve-readiness.ts b/src/main/orcad/orcad-serve-readiness.ts
index 533a7b830b2..59a24465537 100644
--- a/src/main/orcad/orcad-serve-readiness.ts
+++ b/src/main/orcad/orcad-serve-readiness.ts
@@ -2,7 +2,7 @@ import type { ServeReadiness } from '../server/serve-readiness'
 import type { OrcaRuntimeRpcServer } from '../runtime/runtime-rpc'
 import { buildServePairingReadiness } from '../server/serve-pairing-readiness'
 import type { OrcadHealth } from './orcad-health'
-import type { OrcadOptions } from './orcad-entry'
+import type { OrcadOptions } from './orcad-start-contract'
 
 /** The readiness payload orcad publishes once its RPC transport is listening. */
 export async function buildOrcadServeReadiness(input: {
diff --git a/src/main/orcad/orcad-start-contract.ts b/src/main/orcad/orcad-start-contract.ts
new file mode 100644
index 00000000000..e199f5c7cab
--- /dev/null
+++ b/src/main/orcad/orcad-start-contract.ts
@@ -0,0 +1,27 @@
+import type { ServeReadiness } from '../server/serve-readiness'
+import type { OrcadManagedStopContext } from '../../shared/orcad-stop-request'
+
+export type OrcadOptions = {
+  port?: number
+  json?: boolean
+  noPairing?: boolean
+  pairingAddress?: string
+  /** Desktop `orca serve` parity: a mobile-scoped offer with a terminal QR. */
+  mobilePairing?: boolean
+  /** Lets the paired runtime client drive this machine's desktop (computer.*). */
+  grantDesktopControl?: boolean
+  /** Desktop `orca serve` parity: print only the ephemeral-VM recipe line. */
+  recipeJson?: boolean
+  projectRoot?: string
+  /** Literal IP to bind. Defaults to loopback; see orcad-bind-address.ts. */
+  bind?: string
+  /** The browser client's directory; the slot carries none, so `orca serve` passes the app's. */
+  webClientRoot?: string
+}
+
+export type OrcadHandle = {
+  readiness: ServeReadiness
+  /** What an instance-bound stop request must name to stop this process. */
+  managedStop: OrcadManagedStopContext
+  stop(): Promise<void>
+}
diff --git a/src/main/startup/main-process-ready-duplicate-pty-repair.test.ts b/src/main/startup/main-process-ready-duplicate-pty-repair.test.ts
new file mode 100644
index 00000000000..fb19aa455dd
--- /dev/null
+++ b/src/main/startup/main-process-ready-duplicate-pty-repair.test.ts
@@ -0,0 +1,202 @@
+import { mkdtempSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, expect, it, vi } from 'vitest'
+import { getDefaultWorkspaceSession } from '../../shared/constants'
+import type { PersistedState } from '../../shared/persisted-state-types'
+import { agentHookServer } from '../agent-hooks/server'
+import { DelayedAuthority } from '../persistence/loading-store/profile-state-delayed-authority-fixture'
+import { Store } from '../persistence/loading-store/store'
+import { ProfileStateSqliteAuthority } from '../persistence/profile-state/profile-state-sqlite-authority'
+import {
+  emptyTerminalSessionProfile,
+  FIXTURE_GIT_WORKTREE_ID
+} from '../persistence/terminal-topology/terminal-topology-profile-fixture'
+import {
+  leafIds,
+  WindowSession
+} from '../persistence/terminal-topology/terminal-topology-window-session-fixture'
+
+const fixture = vi.hoisted(() => {
+  const value: { state: Record<string, unknown>; userData: string } = {
+    // Account services are stubs: this file pins only the repair's place in readiness.
+    state: {
+      store: null,
+      stats: {},
+      runtime: null,
+      claudeAccounts: {},
+      codexAccounts: {},
+      rateLimits: {}
+    },
+    userData: ''
+  }
+  return value
+})
+
+vi.mock('../../shared/layout-owner-switch', () => ({ ORCA_LAYOUT_OWNER_IS_MAIN: true }))
+vi.mock('../telemetry/client', () => ({ track: vi.fn() }))
+vi.mock('electron', () => ({
+  app: { isPackaged: false, on: vi.fn(), once: vi.fn(), getPath: () => fixture.userData },
+  nativeTheme: {}
+}))
+vi.mock('@electron-toolkit/utils', () => ({ is: { dev: false } }))
+vi.mock('./main-process-state', () => ({ mainProcessState: fixture.state }))
+vi.mock('../runtime/orca-runtime', () => ({
+  OrcaRuntimeService: class {
+    readonly sidebarFacts = null
+    getExistingOrchestrationDb() {
+      return null
+    }
+    rehydrateClientHostedBrowserPages() {}
+    setAgentBrowserBridge() {}
+    setEmulatorBridge() {}
+    setArtifactService() {}
+    setSkillCloudService() {}
+    setAccountServices() {}
+    setCommitMessageAgentEnvironmentResolvers() {}
+  }
+}))
+vi.mock('../runtime/agent-session-claim-identity', () => ({
+  loadAgentSessionClaimSigner: () => null
+}))
+vi.mock('../ai-vault-search/session-search-enablement', () => ({
+  applySessionSearchSettingsChange: vi.fn(),
+  installChildSessionSearchService: () => null
+}))
+vi.mock('../runtime/agent-state-rules/agent-state-rules-live-update', () => ({
+  startAgentStateRulesLiveUpdates: () => {}
+}))
+vi.mock('../artifacts/artifact-cloud-service', () => ({ ArtifactCloudService: class {} }))
+vi.mock('../skills/skill-cloud-service', () => ({ SkillCloudService: class {} }))
+vi.mock('./wsl-orcad-account-env-wiring', () => ({ installWslOrcadAccountShim: vi.fn() }))
+vi.mock('../codex/codex-hook-reconcile', () => ({ startCodexHooks: vi.fn() }))
+vi.mock('../star-nag/service', () => ({
+  StarNagService: class {
+    start = vi.fn()
+    registerIpcHandlers = vi.fn()
+  }
+}))
+vi.mock('../browser/agent-browser-bridge', () => ({
+  AgentBrowserBridge: class {
+    sweepOrphanedSessions = vi.fn()
+  }
+}))
+vi.mock('../emulator/emulator-bridge', () => ({ EmulatorBridge: class {} }))
+vi.mock('../runtime/rpc/dispatcher', () => ({ RpcDispatcher: class {} }))
+vi.mock('../browser/browser-manager', () => ({
+  browserManager: { setBrowserGuestStateChangedListener: vi.fn() }
+}))
+vi.mock('../browser/browser-client-page-automation-runtime', () => ({
+  configureBrowserClientPageAutomationRuntime: vi.fn()
+}))
+vi.mock('../crash-reporting/process-gone-diagnostics', () => ({
+  startPreGoneCrashSampling: vi.fn()
+}))
+vi.mock('./main-window-lifecycle-flags', () => ({ recordProcessGoneCrash: vi.fn() }))
+vi.mock('./gpu-lifecycle', () => ({ handleGpuChildCrash: vi.fn() }))
+vi.mock('./configure-process', () => ({ shouldInstallManagedHooks: () => false }))
+vi.mock('./main-process-observers', () => ({ initializeMainProcessObservers: vi.fn() }))
+vi.mock('./branch-rename-hook', () => ({ installFirstWorkRenameHookSubscription: vi.fn() }))
+vi.mock('./main-process-account-services', () => ({
+  initializeMainProcessAccountServices: vi.fn()
+}))
+vi.mock('./main-process-automations', () => ({ initializeMainProcessAutomations: vi.fn() }))
+vi.mock('./main-process-plugins', () => ({ initializeMainProcessPlugins: vi.fn() }))
+vi.mock('../worktree-trash', () => ({
+  collectWorktreeTrashSweepRoots: vi.fn(),
+  sweepStaleWorktreeTrash: vi.fn()
+}))
+vi.mock('./worktree-removal-records-load', () => ({ loadWorktreeRemovalRecordsForStore: vi.fn() }))
+vi.mock('./first-window-deferral', () => ({ runAfterFirstWindowShown: vi.fn() }))
+vi.mock('./startup-diagnostics', () => ({ logStartupMilestone: vi.fn() }))
+vi.mock('../opencode/opencode-status-plugin-startup-refresh', () => ({
+  refreshInstalledOpenCodeStatusPlugins: vi.fn()
+}))
+vi.mock('../orcad/orcad-artifact-cache-retention', () => ({
+  pruneDesktopOrcadArtifactCache: vi.fn()
+}))
+
+import { initializeReadyRuntimeServices } from './main-process-ready-runtime'
+
+const TAB = 'tab-1'
+const KEPT = '11111111-1111-4111-8111-111111111111'
+const DUPLICATE = '22222222-2222-4222-8222-222222222222'
+const directories: string[] = []
+const stores: Store[] = []
+
+afterEach(async () => {
+  for (const store of stores.splice(0)) {
+    await store.freezeWritesAsync()
+  }
+  vi.restoreAllMocks()
+  for (const directory of directories.splice(0)) {
+    rmSync(directory, { recursive: true, force: true })
+  }
+})
+
+function duplicatePtyProfile(): string {
+  const window = new WindowSession(getDefaultWorkspaceSession())
+  window.addTab(FIXTURE_GIT_WORKTREE_ID, TAB, KEPT)
+  window.setLayout(
+    TAB,
+    {
+      type: 'split',
+      direction: 'vertical',
+      first: { type: 'leaf', leafId: KEPT },
+      second: { type: 'leaf', leafId: DUPLICATE }
+    },
+    { [KEPT]: 'pty-1', [DUPLICATE]: 'pty-1' }
+  )
+  return JSON.stringify({
+    ...JSON.parse(emptyTerminalSessionProfile()),
+    workspaceSession: window.session
+  })
+}
+
+function storedLeafIds(directory: string): string[] {
+  const reader = new ProfileStateSqliteAuthority(join(directory, 'profile-state.db'), 'topology')
+  try {
+    // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: the test wrote this profile as PersistedState.
+    const stored = JSON.parse(reader.readSerializedState() ?? '{}') as PersistedState
+    return leafIds(stored.workspaceSession?.terminalLayoutsByTabId?.[TAB]?.root)
+  } finally {
+    reader.close()
+  }
+}
+
+// Ready services finish before the window opens and RPC starts (main-process-ready.ts:24-31).
+it('finishes the duplicate-terminal repair before ready services resolve, even behind a held write', async () => {
+  const directory = mkdtempSync(join(tmpdir(), 'desktop-duplicate-pty-repair-'))
+  directories.push(directory)
+  fixture.userData = directory
+  const inner = new ProfileStateSqliteAuthority(join(directory, 'profile-state.db'), 'topology')
+  inner.writeSerializedState(Buffer.from(duplicatePtyProfile()))
+  const authority = new DelayedAuthority(inner)
+  const store = new Store({
+    dataFile: join(directory, 'orca-data.json'),
+    profileStateAuthority: authority
+  })
+  stores.push(store)
+  await store.flushPendingOrThrowAsync()
+  fixture.state.store = store
+  vi.spyOn(agentHookServer, 'transferPaneAuthority').mockImplementation(() => {})
+
+  // An earlier profile write is still in flight; the repair queues behind it.
+  const held = authority.pause()
+  store.updateSettings({ agentStatusHooksEnabled: false })
+  const heldWrite = store.flushPendingOrThrowAsync()
+  await held.started.promise
+  let atReady: { memory: string[]; disk: string[] } | null = null
+  const ready = initializeReadyRuntimeServices().then(() => {
+    atReady = {
+      memory: leafIds(store.getWorkspaceSession().terminalLayoutsByTabId[TAB]?.root),
+      disk: storedLeafIds(directory)
+    }
+  })
+  await new Promise((resolve) => setTimeout(resolve, 200))
+  held.finish.resolve()
+  await heldWrite
+  await ready
+
+  expect(atReady).toEqual({ memory: [KEPT], disk: [KEPT] })
+})
diff --git a/src/main/startup/main-process-ready-runtime.ts b/src/main/startup/main-process-ready-runtime.ts
index 55455c3169e..fd07a68723a 100644
--- a/src/main/startup/main-process-ready-runtime.ts
+++ b/src/main/startup/main-process-ready-runtime.ts
@@ -34,6 +34,8 @@ import { runAfterFirstWindowShown } from './first-window-deferral'
 import { logStartupMilestone } from './startup-diagnostics'
 import { refreshInstalledOpenCodeStatusPlugins } from '../opencode/opencode-status-plugin-startup-refresh'
 import { pruneDesktopOrcadArtifactCache } from '../orcad/orcad-artifact-cache-retention'
+import { ORCA_LAYOUT_OWNER_IS_MAIN } from '../../shared/layout-owner-switch'
+import { repairDuplicatePtyPanesOnStart } from '../runtime/moved-pane-owner-rekey'
 
 // Headless serve never opens a window, so the sweep still has to run off a timer there.
 const WORKTREE_TRASH_SWEEP_FALLBACK_MS = 15_000
@@ -143,5 +145,9 @@ export async function initializeReadyRuntimeServices(): Promise<void> {
       void handleGpuChildCrash(details.reason, details.exitCode ?? null, crashedAt)
     }
   })
+  // Switch point: awaited, as it queues behind in-flight writes and every later phase must read its tree.
+  if (ORCA_LAYOUT_OWNER_IS_MAIN) {
+    await repairDuplicatePtyPanesOnStart(store, runtime)
+  }
   logStartupMilestone('services-initialized')
 }
diff --git a/src/main/startup/main-process-runtime-service.ts b/src/main/startup/main-process-runtime-service.ts
index 63837024eb6..ef56b6ef3ef 100644
--- a/src/main/startup/main-process-runtime-service.ts
+++ b/src/main/startup/main-process-runtime-service.ts
@@ -42,8 +42,6 @@ import {
 } from '../runtime/agent-status-observed-pane-identity'
 import { startAgentStateRulesLiveUpdates } from '../runtime/agent-state-rules/agent-state-rules-live-update'
 import { recordDurableCrashBreadcrumb } from '../crash-reporting/durable-crash-breadcrumb'
-import { ORCA_LAYOUT_OWNER_IS_MAIN } from '../../shared/layout-owner-switch'
-import { repairDuplicatePtyPanesOnStart } from '../runtime/moved-pane-owner-rekey'
 
 export function getDesktopWindowStatus(): RuntimeDesktopWindowStatus {
   const activation = state.desktopActivationGate
@@ -148,10 +146,6 @@ export function initializeMainProcessRuntime(): OrcaRuntimeService {
     recordDurableCrashBreadcrumb('agent_state_rules_active', rules)
   )
   state.runtime = runtime
-  // Switch point: main's load repair is written only now that a runtime can move pane owners.
-  if (ORCA_LAYOUT_OWNER_IS_MAIN) {
-    void repairDuplicatePtyPanesOnStart(store, runtime)
-  }
   runtime.sidebarFacts?.attachSidebarAgentStatusStore(agentHookServer)
   agentHookServer.subscribeEnrichedStatus((enriched) =>
     recordObservedAgentStatusPaneIdentity(observedPaneIdentities, enriched.paneKey, runtime)