Reinstalled my phone, any way to check old backups on Microsoft authenticator.

Old Microsoft Authenticator backups cannot be browsed or restored if they were not created before the phone was reinstalled.

For iOS specifically, a valid backup requires that, on the old device, iCloud-based backup was enabled before the reset:

1. iCloud Drive enabled.
2. iCloud Keychain enabled.
3. iCloud Backup enabled, with Authenticator turned on in the Saved to iCloud list.
4. Authenticator updated to version 6.8.33 or later.
5. Authenticator opened at least once after backup was enabled.

If these conditions were not met on the old device before it was wiped/reinstalled, there is no previous Authenticator backup available to restore, and turning on backup after reinstall only starts a new backup from the current (empty) state.

If a proper backup did exist from the old device and you are on iOS, try on the new device:

1. Uninstall the Authenticator app.
2. Reinstall Authenticator.
3. Open it and use the Restore from backup / recovery option (for iOS this will use iCloud, for Android the recovery account), then sign in with the same account used for backup.

If no earlier backup appears after following these steps, the previous data is not recoverable and each account’s MFA must be re-registered using its own recovery options (for example, account recovery flows, backup codes, or admin/helpdesk reset for work or school accounts).

References:

• Back up your accounts in Microsoft Authenticator
• Microsoft Authenticator FAQs
• Restore account credentials from Microsoft Authenticator