ORA-01110: data file 1 while duplicate database from physical standby

Scope: While duplicating database from standby database, you might be getting below error message as recovery is required for datafile 1. 

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of Duplicate Db command at 04/10/2014 17:33:30

RMAN-05501: aborting duplication of target database

RMAN-03015: error occurred in stored script Memory Script

RMAN-06136: ORACLE error from auxiliary database: ORA-01194: file 1 needs more recovery to be consistent

ORA-01110: data file 1: '+DATA/NEERDUP/datafile/system.1428.489328707'

Cause:
This error comes when you have not stopped the Archive log shipping from primary database and MRP is running at standby database. 

Solution:
Stop the log shipping and keep the database recovery running on standby Database and standby is in OPEN READ ONLY APPLY mode:

1.  Stop the redo log ship from primary : 

alter system set log_archive_dest_state_2=defer scope=spfile sid=’*’;   

2. Connect with net service with standby database as target and NEERDUP name as auxiliary database. Run the duplicate command. 

RMAN> duplicate target database to <DB_NAME> from active database;

3. Start the redo log ship from primary : 

alter system set log_archive_dest_state_2=enable scope=spfile sid=’*’;