ORA-12557: TNS:protocol adapter not loadable

this problem On windows Platforms .

and it must be related to Windows Environment or Oracle Home PATH because sqlplus command works smoothly when I execute it inside ORACLE_HOME\bin.

RUN: SYSDM.CPL to open Windows System Properties
Click on Advanced Tab > Environment Variables…

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

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.

Or i Don’t love this way , Since its not actual solution but its solve problem sometimes :
1-Remove ORACLE_HOME From environment Variable .

2- Restart PC 

Osama mustafa 

21 thoughts on “ORA-12557: TNS:protocol adapter not loadable

  1. “change the order between Oracle Client Home and Oracle DB Home” SOLVES, ORA-12560 : TNS: protocol adapter error as well as ORA-12557Thanks you again, Osama Mustafa.What would we do without you,Mike


  2. Dear Mustafa am really in a bad need to your helpi have a oracle 12c DB 64bit installed on my win serv 2012and installed oracle client 11g 32as i need to open connection through client between unix server and windowsand always recives orror like 125557 please in a bad need to ur help


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