ORA-01586 ORA-39701 database must be mounted EXCLUSIVE and not open for this operation

Dropping the database :

 
Mount the database in restrict mode:
 SQL> startup mount restrict;
ORACLE instance started.


Database mounted.

SQL> select instance_name from v$instance;

INSTANCE_NAME
----------------
dbm1

SQL> drop database;

Database dropped.

What if you get the below error:


SQL> startup mount  restrict;
ORACLE instance started.


Database mounted.
SQL> drop database;
drop database
*
ERROR at line 1:
ORA-01586: database must be mounted EXCLUSIVE and not open for this operation

Even the startup upgrade will fail:

SQL> startup upgrade
ORACLE instance started.

Total System Global Area 3206836224 bytes
Fixed Size                  2232640 bytes
Variable Size             704646848 bytes
Database Buffers         2348810240 bytes
Redo Buffers              151146496 bytes
Database mounted.
ORA-01092: ORACLE instance terminated. Disconnection forced
ORA-39701: database must be mounted EXCLUSIVE for UPGRADE or DOWNGRADE
Process ID: 46501
Session ID: 652 Serial number: 3


Then mostly likely you are destroying a RAC database and you need to change the cluster_database=FALSE.

SQL> alter system set cluster_database=FALSE scope=spfile;


System altered.

SQL> startup mount restrict;
ORACLE instance started.


Redo Buffers              151146496 bytes
Database mounted.

SQL> select instance_name from v$instance;

INSTANCE_NAME
----------------
dbm1

SQL> drop database;

Database dropped.