
Problem
While using SQL Developer you’ve encountered the error ORA-12705: Cannot Access NLS data files or invalid environment specified, but don’t know how to resolve this issue. Below are step that should be taken to resolve the issue.
Resolving ORA-12705 Cannot Access NLS data files or invalid environment specified
- Locate and open your SQL Developer folder.
- Locate the
/bin/
folder by browsing to the locationsqldeveloper/sqldeveloper/bin/
- Locate and open the sqldeveloper.conf using a text editor. Notepad++ works fine.
- Copy and paste and save the following lines to the file:
# Resolving ORA-12705 Cannot Access NLS data files or invalid environment specified AddVMOption -Duser.language=en AddVMOption -Duser.region=US AddVMOption -Duser.country=en
- Restart SQL Developer
- For a working example on how to fix/resolve the error ORA-12705: Cannot Access NLS data files or invalid environment specified, please see the animated GIF. Below.

Conclusion
Applying the fix above will fix the error : “ORA-12705: Cannot Access NLS data files or invalid environment specified”. If the error still persist, please ensure that you follow the steps precisely and all the files are properly saved.