ORA-01033: ORACLE initialization or shutdown in progress

What does it mean?

The database instance you are connecting to is in the middle of startup (mount/open) or shutdown. Normal user connections are not accepted in this intermediate state.

Why does it happen?

The instance is stuck in NOMOUNT/MOUNT (e.g. awaiting media recovery), a SHUTDOWN is in progress, or the database is hung before reaching OPEN due to an error. Connecting to a freshly started instance before startup completes also returns this error.

How to fix it

Connect as SYSDBA and check the state: sqlplus / as sysdba; then SELECT status FROM v$instance; and SELECT open_mode FROM v$database; Try opening the instance: ALTER DATABASE OPEN; If recovery is required, run RECOVER DATABASE; then open it. Find the underlying error preventing open in the alert.log (missing/corrupt datafile, redo). If shutdown is hung, try SHUTDOWN ABORT followed by STARTUP.