How do I reinstate my Microsoft authenticator on my IPhone?

To reinstate Microsoft Authenticator on an iPhone, use backup and restore if it was previously backed up, or add the accounts again if not.

1. Make sure backup was enabled on the old iPhone (required for restore):
   • iCloud Drive enabled.
   • iCloud Keychain enabled.
   • iCloud Backup enabled and Authenticator turned on in the Saved to iCloud list.
   • Authenticator updated to version 6.8.33 or later and opened at least once before switching phones.
2. Restore Authenticator on the new iPhone (same iOS platform only):
   • Install Microsoft Authenticator from the App Store.
   • Ensure iCloud Drive, iCloud Keychain, and iCloud Backup are enabled on the new iPhone.
   • Open Authenticator and choose Begin recovery (or sign in as prompted) with the same Microsoft account used for backup.
   • Your backed-up accounts will be restored.
   • For each account that shows Action required, tap it and sign in again to complete verification.
3. If backup does not appear on the new iPhone:
   • On the old device, verify the iCloud settings and Authenticator version as above, then open the app once.
   • On the new device, uninstall and reinstall Authenticator; the backup should then appear.
4. What is restored:
   • Microsoft personal accounts using only a one-time password (OTP): codes are restored.
   • Microsoft personal accounts with passwordless sign-in: only the account name is restored; sign-in is required again.
   • Work or school accounts: only the account name is restored; sign-in is required again.
   • Third-party accounts (Amazon, Facebook, Gmail, etc.): OTP codes are restored.
5. If unable to restore from backup:
   • Add the accounts again using each service’s security/MFA setup page.
   • If the issue is that the iCloud or backup account itself cannot be accessed, contact Apple Support.
   • If the issue is that the Microsoft backup account cannot be accessed, use the Microsoft account sign-in helper to regain access, then try restore again.

References:

• Microsoft Authenticator FAQs
• Back up your accounts in Microsoft Authenticator
• Restore account credentials from Microsoft Authenticator
• Migrate to a new iPhone for work