ORA-01031: insufficient privileges (on Windows)

When you have this error, here is a few things to check:

• you have your password file. If not, recreate it:

orapwd file=c:\.....\database\PWD{SID}.ora force=[y/n] 

Carefull for linux DBA, the file is named differentely on Windows - PWD{ORACLE_SID}.ora (ex. PWDORCL.ora), it kepts me looking for a solution to this problem a loonnnng time...

• remote_login_passwordfile must be set to EXCLUSIVE

• If you have two runtime running on the same server (10g and 11g for example), set the TNS_ADMIN environement variable with the location of your sqlnet.ora, listener.ora and tnsnames.ora files

• The oracle user is in the right group (dba)

• Add this line into your sqlnet.ora file (haven't done it yet, but it supposed to fix the issue)

SQLNET.AUTHENTICATION_SERVICES = (NTS)