diff --git a/src/main/persistence.ts b/src/main/persistence.ts
index 8feb90a3298..48321b3b11d 100644
--- a/src/main/persistence.ts
+++ b/src/main/persistence.ts
@@ -6604,6 +6604,38 @@ export class Store {
     return true
   }
 
+  migrateLegacySshRemotePtyLeaseGeneration(
+    targetId: string,
+    ptyId: string,
+    relayInstanceId: string
+  ): boolean {
+    const relayPtyId = this.getRelayPtyIdForSshLeaseStorage(targetId, ptyId)
+    const lease = this.state.sshRemotePtyLeases?.find(
+      (entry) =>
+        entry.targetId === targetId &&
+        entry.ptyId === relayPtyId &&
+        entry.relayInstanceId === undefined
+    )
+    if (!lease) {
+      return false
+    }
+    const now = Date.now()
+    lease.relayInstanceId = relayInstanceId
+    lease.state = 'attached'
+    lease.updatedAt = now
+    lease.lastAttachedAt = now
+    // Why: crash-safe adoption must remain O(1) per restored pane instead of
+    // synchronously serializing the full persisted store during startup.
+    this.persistTerminalTeardownIntents({
+      kind: 'ssh-migrate-generation',
+      targetId,
+      ptyId: relayPtyId,
+      relayInstanceId,
+      attachedAt: now
+    })
+    return true
+  }
+
   markSshRemotePtyShutdownRequested(targetId: string, ptyId: string): boolean {
     const requestedGeneration = parseAppSshPtyId(ptyId)?.relayInstanceId
     const relayPtyId = this.getRelayPtyIdForSshLeaseStorage(targetId, ptyId)
diff --git a/src/main/ssh/ssh-relay-generation-reattach.test.ts b/src/main/ssh/ssh-relay-generation-reattach.test.ts
index 210ca3af436..1ca543af27c 100644
--- a/src/main/ssh/ssh-relay-generation-reattach.test.ts
+++ b/src/main/ssh/ssh-relay-generation-reattach.test.ts
@@ -1,7 +1,20 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { mkdtempSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
 import { SshRelaySession } from './ssh-relay-session'
+import { Store } from '../persistence'
 import { createMockDeps, mockDeploySuccess } from './ssh-relay-session-test-fixtures'
 
+vi.mock('electron', () => ({
+  app: { getPath: () => process.cwd() },
+  safeStorage: {
+    isEncryptionAvailable: () => true,
+    encryptString: (plaintext: string) => Buffer.from(`encrypted:${plaintext}`, 'utf-8'),
+    decryptString: (ciphertext: Buffer) => ciphertext.toString('utf-8').slice('encrypted:'.length)
+  }
+}))
+
 vi.mock('./ssh-relay-deploy', () => ({ deployAndLaunchRelay: vi.fn() }))
 
 vi.mock('./ssh-channel-multiplexer', () => ({
@@ -17,8 +30,10 @@ vi.mock('./ssh-channel-multiplexer', () => ({
 }))
 
 vi.mock('../providers/ssh-pty-provider', () => ({
-  isSshPtyNotFoundError: () => false,
-  isSshPtyIdentityMismatchError: () => false,
+  isSshPtyNotFoundError: (err: unknown) =>
+    (err instanceof Error ? err.message : String(err)).includes('not found'),
+  isSshPtyIdentityMismatchError: (err: unknown) =>
+    (err instanceof Error ? err.message : String(err)).includes('identity mismatch'),
   SshPtyProvider: class MockSshPtyProvider {
     onData = vi.fn().mockReturnValue(() => {})
     onReplay = vi.fn().mockReturnValue(() => {})
@@ -133,4 +148,93 @@ describe('SSH relay generation reattach', () => {
       code: -1
     })
   })
+
+  it('migrates a legacy lease only after the current relay proves it can attach', async () => {
+    const dir = mkdtempSync(join(tmpdir(), 'orca-legacy-ssh-lease-'))
+    const dataFile = join(dir, 'state.json')
+    const store = new Store({ dataFile })
+    const reloadedStores: Store[] = []
+    try {
+      store.upsertSshRemotePtyLease({
+        targetId: 'target-1',
+        ptyId: 'pty-legacy',
+        state: 'detached'
+      })
+      const synchronousFlush = vi.spyOn(store, 'flush')
+      const { mockConn, mockPortForward, getMainWindow } = createMockDeps()
+      const attachForReconnect = vi.fn().mockResolvedValue({})
+      vi.mocked(getSshPtyProvider).mockReturnValue({
+        attachForReconnect,
+        getRelayInstanceId: () => 'relay-current',
+        dispose: vi.fn()
+      } as unknown as ReturnType<typeof getSshPtyProvider>)
+      vi.mocked(getPtyIdsForConnection).mockReturnValue([])
+
+      const session = new SshRelaySession('target-1', getMainWindow, store, mockPortForward)
+      await session.establish(mockConn)
+
+      expect(attachForReconnect).toHaveBeenCalledWith('pty-legacy')
+      expect(store.getSshRemotePtyLeases('target-1')).toEqual([
+        expect.objectContaining({
+          ptyId: 'pty-legacy',
+          relayInstanceId: 'relay-current',
+          state: 'attached',
+          lastAttachedAt: expect.any(Number)
+        })
+      ])
+      expect(synchronousFlush).not.toHaveBeenCalled()
+      const reloaded = new Store({ dataFile })
+      reloadedStores.push(reloaded)
+      expect(reloaded.getSshRemotePtyLeases('target-1')[0]).toEqual(
+        expect.objectContaining({ relayInstanceId: 'relay-current', state: 'attached' })
+      )
+    } finally {
+      store.flush()
+      for (const reloaded of reloadedStores) {
+        reloaded.flush()
+      }
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
+
+  it('expires a failed legacy identity without adopting the current relay generation', async () => {
+    const dir = mkdtempSync(join(tmpdir(), 'orca-stale-ssh-lease-'))
+    const store = new Store({ dataFile: join(dir, 'state.json') })
+    try {
+      store.upsertSshRemotePtyLease({
+        targetId: 'target-1',
+        ptyId: 'pty-recycled',
+        state: 'detached'
+      })
+      const { mockConn, mockPortForward, getMainWindow, mockWindow } = createMockDeps()
+      const attachForReconnect = vi
+        .fn()
+        .mockRejectedValue(new Error('PTY "pty-recycled" not found (identity mismatch)'))
+      vi.mocked(getSshPtyProvider).mockReturnValue({
+        attachForReconnect,
+        getRelayInstanceId: () => 'relay-current',
+        dispose: vi.fn()
+      } as unknown as ReturnType<typeof getSshPtyProvider>)
+      vi.mocked(getPtyIdsForConnection).mockReturnValue([])
+
+      const session = new SshRelaySession('target-1', getMainWindow, store, mockPortForward)
+      await session.establish(mockConn)
+
+      expect(store.getSshRemotePtyLeases('target-1')).toEqual([
+        expect.objectContaining({ ptyId: 'pty-recycled', state: 'expired' })
+      ])
+      expect(store.getSshRemotePtyLeases('target-1')[0]?.relayInstanceId).toBeUndefined()
+      expect(mockWindow.webContents.send).toHaveBeenCalledWith('pty:exit', {
+        id: 'ssh:target-1@@pty-recycled',
+        code: -1
+      })
+      expect(setPtyOwnership).not.toHaveBeenCalledWith(
+        'ssh:target-1@@relay-current@@pty-recycled',
+        'target-1'
+      )
+    } finally {
+      store.flush()
+      rmSync(dir, { recursive: true, force: true })
+    }
+  })
 })
diff --git a/src/main/ssh/ssh-relay-session.ts b/src/main/ssh/ssh-relay-session.ts
index 2215d984292..3a95c59dfda 100644
--- a/src/main/ssh/ssh-relay-session.ts
+++ b/src/main/ssh/ssh-relay-session.ts
@@ -1244,6 +1244,7 @@ export class SshRelaySession {
         })
         .filter((entry): entry is [string, ExpectedPtyIdentity] => entry !== null)
     )
+    const leaseByPtyId = new Map(attachableLeases.map((lease) => [lease.ptyId, lease]))
     // Why: after app restart, ptyOwnership is empty but durable SSH leases
     // still describe remote PTYs that survived in the relay grace window.
     const ownedPtyIds = getPtyIdsForConnection(this.targetId).flatMap((appPtyId) => {
@@ -1276,15 +1277,35 @@ export class SshRelaySession {
           return
         }
         const appPtyId = toAppSshPtyId(this.targetId, ptyId, relayInstanceId)
+        const lease = leaseByPtyId.get(ptyId)
+        if (lease && !lease.relayInstanceId && relayInstanceId) {
+          // Why: only a proven attach can bind a pre-generation lease to the
+          // relay boot that actually owns it; strict normal writes stay fenced.
+          const migrated = this.store.migrateLegacySshRemotePtyLeaseGeneration(
+            this.targetId,
+            ptyId,
+            relayInstanceId
+          )
+          if (!migrated && !this.store.markSshRemotePtyLease(this.targetId, appPtyId, 'attached')) {
+            continue
+          }
+        } else {
+          this.store.markSshRemotePtyLease(this.targetId, appPtyId, 'attached')
+        }
         setPtyOwnership(appPtyId, this.targetId)
-        this.store.markSshRemotePtyLease(this.targetId, appPtyId, 'attached')
         this.forwardReattachReplay(appPtyId, attachResult.replay ?? '')
       } catch (err) {
         if (!isSshPtyNotFoundError(err)) {
           throw err
         }
-        const appPtyId = toAppSshPtyId(this.targetId, ptyId, relayInstanceId)
-        if (isSshPtyIdentityMismatchError(err)) {
+        const lease = leaseByPtyId.get(ptyId)
+        const isLegacyLease = Boolean(lease && !lease.relayInstanceId && relayInstanceId)
+        const appPtyId = toAppSshPtyId(
+          this.targetId,
+          ptyId,
+          isLegacyLease ? undefined : relayInstanceId
+        )
+        if (isSshPtyIdentityMismatchError(err) && !isLegacyLease) {
           console.warn(
             `[ssh-relay-session] Ignoring stale PTY ${ptyId} for ${this.targetId} after relay identity mismatch: ${
               err instanceof Error ? err.message : String(err)
@@ -1297,17 +1318,9 @@ export class SshRelaySession {
             err instanceof Error ? err.message : String(err)
           }`
         )
-        clearProviderPtyState(appPtyId)
-        deletePtyOwnership(appPtyId)
-        this.forwardedReattachReplayByPty.delete(appPtyId)
-        this.store.markSshRemotePtyLease(this.targetId, appPtyId, 'expired')
-        // Why: if the new relay cannot reattach this id, the remote backing
-        // process is gone. Tell the renderer so it clears stale pane bindings
-        // instead of keeping a cursor-only terminal.
-        const win = this.getMainWindow()
-        if (win && !win.isDestroyed()) {
-          win.webContents.send('pty:exit', { id: appPtyId, code: -1 })
-        }
+        // Why: a failed legacy attach has not earned the new generation. Retire
+        // and notify its original id so a recycled current relay id stays intact.
+        this.expireReattachPty(ptyId, appPtyId)
       }
     }
   }
diff --git a/src/main/terminal-teardown-intent-records.ts b/src/main/terminal-teardown-intent-records.ts
index b60932af778..f5ba04497b9 100644
--- a/src/main/terminal-teardown-intent-records.ts
+++ b/src/main/terminal-teardown-intent-records.ts
@@ -69,6 +69,15 @@ export const terminalTeardownIntentJournalRecordSchema = z.discriminatedUnion('k
   journalBaseSchema
     .extend({ kind: z.literal('runtime-remove-environment'), environmentId: nonEmptyString })
     .strict(),
+  journalBaseSchema
+    .extend({
+      kind: z.literal('ssh-migrate-generation'),
+      targetId: nonEmptyString,
+      ptyId: nonEmptyString,
+      relayInstanceId: nonEmptyString,
+      attachedAt: timestamp
+    })
+    .strict(),
   journalBaseSchema
     .extend({
       kind: z.literal('ssh-set'),
@@ -93,6 +102,13 @@ export type TerminalTeardownIntentMutation =
   | { kind: 'runtime-upsert'; request: PersistedRuntimeTerminalClose }
   | { kind: 'runtime-remove'; environmentId: string; handle: string }
   | { kind: 'runtime-remove-environment'; environmentId: string }
+  | {
+      kind: 'ssh-migrate-generation'
+      targetId: string
+      ptyId: string
+      relayInstanceId: string
+      attachedAt: number
+    }
   | {
       kind: 'ssh-set'
       targetId: string
diff --git a/src/main/terminal-teardown-intent-snapshot.ts b/src/main/terminal-teardown-intent-snapshot.ts
index 297383330e0..a6b5d3224d0 100644
--- a/src/main/terminal-teardown-intent-snapshot.ts
+++ b/src/main/terminal-teardown-intent-snapshot.ts
@@ -182,6 +182,22 @@ function applyJournalRecord(
         (entry) => entry.environmentId !== record.environmentId
       )
       return
+    case 'ssh-migrate-generation': {
+      const lease = state.sshRemotePtyLeases?.find(
+        (candidate) =>
+          candidate.targetId === record.targetId &&
+          candidate.ptyId === record.ptyId &&
+          candidate.relayInstanceId === undefined
+      )
+      if (!lease) {
+        return
+      }
+      lease.relayInstanceId = record.relayInstanceId
+      lease.state = 'attached'
+      lease.updatedAt = Math.max(lease.updatedAt, record.attachedAt)
+      lease.lastAttachedAt = Math.max(lease.lastAttachedAt ?? 0, record.attachedAt)
+      return
+    }
     case 'ssh-set': {
       const lease = state.sshRemotePtyLeases?.find(
         (candidate) =>