ORA-01031: insufficient privileges

ORA-01031: insufficient privileges
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ABOVE ERROR MAY OCCUR IN FOLLOWING SITUATIONS...

1. Absent/corrupted PASSWORD FILE (Remote connection)
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The issue here is the ablity to connect to your instance remotely as
sysdba; this requires

1. a password file generated by orapwd and

2. an init.ora parameter, remote_login_passwordfile, set to shared or
exclusive .If this parameter is set to NONE then no password file is utilised and no possibility exists of a remote login with sys as sysdba.

To solve the problem:

Delete old password file manually(OS delete).
then create new one.

to create a password file :

C:\Documents and Settings\user> orapwd file=G:\oracle\product\10.2.0\db_1\database\PWDBEFTN.ora password=sys entries=5


2. Lack of privileges
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In most cases, the user receiving this error lacks a privilege to create an object (such as a table, view, procedure and the like).
Grant the required privilege .

grant create table to user;


3. Startup
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If someone receives this error while trying to startup the instance,
the logged on user must belong to the ora_dba group on Windows or dba group on Unix.
To add a user to the ora_dba group on Windows, net localgroup should help:
C:\> net localgroup ora_dba rene /add

4. In windows (Local machine)
=====================
Windows does this on occasion, usually when domain accounts are used.
Ensure you are using a local user account (even domain accounts allow local
logins when the network is absent)