ora-00275: media recovery has already been started

Cause: An attempt was made to start a second media recovery operation in the same session.
Action: Complete or cancel the first media recovery session or start another session to perform media recovery.

la recuperación del medio físico ya se ha iniciado
récupération après défaillance matérielle déjà commencée
Media Recovery hat bereits begonnen
recuperação do suporte magnético já foi iniciada