ora-12705 cannot access nls data files or invalid environment specified

Suppose we are getting below error while connectiong Database with SQL Developer :

ora-12705 cannot access nls data files or invalid environment specified

1. Open SQL Developer package content. Go to Applications, right click on SQL Developer and select "Show Package Contents".
2. Go to Contents/Resources/sqldeveloper/sqldeveloper/bin/
3. Open sqldeveloper.conf using a text editor.
4. Add the following lines: 

# Options to avoid "ORA-12705: Cannot access NLS data files or invalid environment specified." 

AddVMOption -Duser.language=en 

AddVMOption -Duser.region=US 

AddVMOption -Duser.country=en

5. Restart SQL Developer

We can also use below command if issue occurs after login :

ALTER SESSION SET NLS_LANGUAGE= 'AMERICAN' NLS_TERRITORY= 'AMERICA' NLS_CURRENCY= '$' NLS_ISO_CURRENCY= 'AMERICA' NLS_NUMERIC_CHARACTERS= '.,' NLS_CALENDAR= 'GREGORIAN' NLS_DATE_FORMAT= 'DD-MON-RR' NLS_DATE_LANGUAGE= 'AMERICAN' NLS_SORT= 'BINARY'