Oracle database: While enabling archivelog mode ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

While trying to change the database into archivelog mode I got this error:
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SQL> alter database archivelog;
alter database archivelog
*
ERROR at line 1:
ORA-00265: instance recovery required, cannot set ARCHIVELOG mode

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Do not close the database in a way that it will require instance recovery(e.g. shutdown abort)
before you will mount it for archivelog mode change otherwise you
will get the below error "ORA-00265", always try to shutdown the database gracefully
by using "shutdown immediate".

SQL> alter system checkpoint;

System altered.

SQL> shutdown abort

ORACLE instance shut down.

SQL> startup restrict

ORACLE instance started.

Total System Global Area  456146944 bytes

Fixed Size                  1344840 bytes

Variable Size             381684408 bytes

Database Buffers           67108864 bytes

Redo Buffers                6008832 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  456146944 bytes

Fixed Size                  1344840 bytes

Variable Size             381684408 bytes

Database Buffers           67108864 bytes

Redo Buffers                6008832 bytes

Database mounted.

SQL> alter database archivelog;

Database altered.

SQL> alter database open;

Database altered.

SQL> archive log list

Database log mode              Archive Mode

Automatic archival             Enabled

Archive destination            /home/oracle/oracle11g

Oldest online log sequence     438

Next log sequence to archive   440

Current log sequence           440                                                     

ORA-1653: unable to extend table SYS.AUD$ by 512 in tablespace SYSTEM

ORA-1653: unable to extend table SYS.AUD$ by 512 in tablespace SYSTEM

ORA-1653: unable to extend table SYS.AUD$ by 512 in tablespace SYSTEM


when I saw the allert log.

"alert.log" 

ORA-1653: unable to extend table SYS.AUD$ by 512 in tablespace SYSTEM

and even I cannot login into the DB via TOAD.

so logged into the unix server directly and invoked the sqlplus.
and then backed up the aud$ table and truncated the data in it.

SQL> select count(*) from aud$;

COUNT(*)
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200055


SQL> Create table aud_backup tablespace users as select * from aud$ ;

Table created.

SQL> truncate table aud$;

Table truncated.

SQL> select count(*) from aud$;

COUNT(*)
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0