I added a new datafile to the primary database, but not automatically added on standby.

ORA-00283: recovery session canceled due to errors
ORA-01111: name for data file 129 is unknown – rename to correct file
ORA-01110: data file 129: ‘C:\ORACLE\ORA10G\DATABASE\UNNAMED00129’
ORA-01157: cannot identify/lock data file 129 – see DBWR trace file
ORA-01111: name for data file 129 is unknown – rename to correct file
ORA-01110: data file 129: ‘C:\ORACLE\ORA10G\DATABASE\UNNAMED00129’

Solution:

Note: It can run on umount state

1- Check the name of the datafile on standby database
SQL> select name from v$datafile; —- This command should show the datafile name as UNNAMEDxxxxx

2- On the standby database
SQL> alter system set standby_file_management=’manual’;

3- On the standby database rename the datafile
SQL> alter database create datafile ‘C:\ORACLE\ORA10G\DATABASE\UNNAMED00129’ as ‘C:\ORACLE\ORA10G\DATABASE\actual_dbfile_name.dbf’

4- On the standby database
SQL> alter system set standby_file_management=’auto’;

5- On the standby database
SQL> recover managed standby database disconnect;