Fast DBA: ORA-12557: TNS:protocol adapter not loadable

Problem:

You are getting ORA-12557 while running Oracle on Windows.

ORA-12557 is usually related to Microsoft Windows environments and Oracle HOME PATH variable.

Solution:

Put the Oracle DB Home in front of the other paths in the PATH environment variable.

Remove ORACLE_HOME From environment Variable and restart PC.

Open: Control Panel -> All Control Panel Items -> System -> Advanced system settings

Click: Environment Variables

Select Path variable under System Variable, then click Edit:

Change the order between Oracle Client Home and Oracle DB Home:

From: D:\oracle\product\11.2.1\client_1;D:\oracle\product\12.1.0.1\db_1;

To: D:\oracle\product\12.1.0.1\db_1;D:\oracle\product\11.2.1\client_1;

Put desired Oracle home in the front of the other path

I hope this helps.

Please feel free to leave your questions or suggest improvements to this section.

Fast DBA