Oracle : Ошибка ORA-19955

"only one open thread is allowed to change the DBID"
*Cause: The operation failed because there were active threads in the
database. The most likely cause is that the database crashed the
last time it was shut down.
*Action: Ensure that all threads are closed before retrying
the operation. Start and open the database
to perform crash recovery, then shut down with the NORMAL
or IMMEDIATE options to close it cleanly. Finally, try running
the utility again.

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