Oracle Error ORA-12557 – TNS:protocol adapter not loadable occurs on my Windows machine whenever I want to access sqlplus using command prompt.

Once hit [Enter] button after issuing command sqlplus / as sysdba, an unwanted popup appear  and it said:

The procedure entry point snlseFreeSecAttrib could not be located in the dynamic link library oranl10.dll

I don’t really know how come this error come hehe, but it must be related to Windows Environment or Oracle Home PATH because sqlplus command works smoothly when I execute it inside ORACLE_HOME\bin.

Okay, let we see what’s wrong with the Windows Environment.

RUN: SYSDM.CPL to open Windows System Properties

Click on Advanced Tab > Environment Variables…

Click the Path variable under System Variable, then click  Edit…

This is the original Path

Let we change the order between Oracle Client Home and Oracle DB Home:

From: D:\oracle\product\10.2.0\client_1\bin;D:\oracle\product\10.2.0\db_1\bin;

To: D:\oracle\product\10.2.0\db_1\bin;D:\oracle\product\10.2.0\client_1\bin;

in other words, put the Oracle DB Home in front of the other path.

Click OK to save the changes.

Open new command prompt and write down sqlplus / as sysdba

Eh, it work..