ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

SQL> startup mount
ORACLE instance started.

Total System Global Area 6265438208 bytes
Fixed Size 2169816 bytes
Variable Size 5167383592 bytes
Database Buffers 1073741824 bytes
Redo Buffers 22142976 bytes
Database mounted.

SQL> archive log list
Database log mode No Archive Mode
Automatic archival Disabled
Archive destination +ARCH
Oldest online log sequence 180
Current log sequence 182
SQL> alter database archivelog;
alter database archivelog
*
ERROR at line 1:
ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

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


Database dismounted.
ORACLE instance shut down.


Cause:

The database was crashed itself or you issued shutdown abort or startup force commands.

--->you must shutdown your database gracefully/cleanly(normal,transaction or immediate)

oratest@ctsst $ sqlplus "/as sysdba"

SQL*Plus: Release 11.2.0.2.0 Production on Fri Aug 23 19:23:31 2013

Copyright (c) 1982, 2010, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 6265438208 bytes
Fixed Size 2169816 bytes
Variable Size 5167383592 bytes
Database Buffers 1073741824 bytes
Redo Buffers 22142976 bytes
Database mounted.
Database opened.
SQL>shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.

Total System Global Area 6265438208 bytes
Fixed Size 2169816 bytes
Variable Size 5167383592 bytes
Database Buffers 1073741824 bytes
Redo Buffers 22142976 bytes
Database mounted.
SQL> alter database archivelog;

Database altered.
SQL>

SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination +ARCH
Oldest online log sequence 180
Next log sequence to archive 182