Oracle Message ORA-01616 - instance string (thread string) is open - cannot disable

ERRORinstance string (thread string) is open - cannot disable
CAUSEThe thread is not closed. The last instance to use the thread died leaving the thread open. A thread cannot be disabled until it is closed. It is still required for crash or instance recovery.
ACTIONIf the database is open, instance recovery should close the thread soon - wait a few minutes. Otherwise open the database - crash recovery will close the thread.