This issue often occurs in a Oracle database 12c&onward installation or restore operation. The error stated that multitenant container database not set up properly, which means we have to set the enable_pluggable_database to True while on restore steps.

To fix this, connect to your Oracle Database using the sysdba user:

sqlplus / as sysdba

startup nomount

Change the value of the enable_pluggable_database system parameter by typing:

ALTER SYSTEM SET “enable_pluggable_database”= TRUE SCOPE = SPFILE;

COMMIT;

Now, restart your db, now you can mount the database:

shutdown immediate

startup mount or startup