In standby ... ORA-01153: an incompatible media recovery is active

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION
*
ERROR at line 1:
ORA-01153: an incompatible media recovery is active


This indicates that currently running media recovery process i.e. standby active 

SQL> alter database recover managed standby database cancel;   --- Cancel first 

Database altered.

SQL>  ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;
Database altered.

==================

SQL>  ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;
 ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT
*
ERROR at line 1:
ORA-01153: an incompatible media recovery is active


SQL> select PROCESS,CLIENT_PROCESS,THREAD#,SEQUENCE#,BLOCK# from v$managed_standby where process = 'MRP0' or client_process='LGWR';

PROCESS   CLIENT_P    THREAD#  SEQUENCE#     BLOCK#
--------- -------- ---------- ---------- ----------
RFS       LGWR              1        444      55512   <<<<< Kill or restart the standby 

remote file server (RFS)
Managed Recovery Process (MRP)


SQL> shutdown immediate ;
ORA-01109: database not open


Database dismounted.
ORACLE instance shut down.
SQL> startup mount ;
ORACLE instance started.

Total System Global Area  536870912 bytes
Fixed Size                  8794848 bytes
Variable Size             306187552 bytes
Database Buffers          213909504 bytes
Redo Buffers                7979008 bytes
Database mounted.
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;

Database altered.