Now that we are fully into database upgrades, here is an important item to be aware of:
As you may know, the Database Vault (DV) option could be reported as not installed in source when converting non-CDB to PDB, and the target CDB has the option installed. However, be aware that is not supported to remove DV option in a multi-tenant environment (single-tenant included).
From Doc ID 2380950.1:
IMPORTANT: Never run dvremov.sql on a container database (CDB) / Multitenant environment. Doing so will cause serious problems when upgrading the PDBs.
In case you run dvremov.sql in a 12c multi-tenant DB, then the only option you might have is to restore the database to the state before running dvremov.sql. Assuming you have this backup, of course.
So stay sharp!
How To uninstall / install Database Vault in a 12c database ? (Doc ID 2112167.1)
DBA_DV_STATUS Is INVALID (Due to “ORA-00942: Table Or View Does Not Exist”) (Doc ID 2380950.1)