Oracle Error Message
RMAN-20002: target database already registered in recovery catalog
Reason for the Error
target database is already registered in the recovery catalog
Solution
if the target database is really registered, there is no need to register it again. Note that the recovery catalog enforces that all databases have a unique DBID. If the new database was created by copying files from an existing database, it will have the same DBID as the original database and cannot be registered in the same recovery catalog.