SP2-1503: Unable to initialize Oracle call interface

I got ” SP2-1503: Unable to initialize Oracle call interface ”  error in Oracle database.

SP2-1503: Unable to initialize Oracle call interface

Details of error are as follows.

SP2-1503: Unable to initialize Oracle call interface

Cause: Indicates a library used by SQL*Plus to communicate with the database failed to initialize correctly.

Action: Check that the Oracle environment or registry entries are consistent and correct.
 If using the SQL*Plus Instant Client make sure the SQL*Plus and Oracle libraries are
 from the same release. Make sure you have read access to the libraries.

sqlplus / as sysdba
SP2-1503: Unable to initialize Oracle call interface
SP2-0152: ORACLE may not be functioning properly

Unable to initialize Oracle call interface

This SP2-1503 error is related to the Indicates a library used by SQL*Plus to communicate with the database failed to initialize correctly.

Check that the Oracle environment or registry entries are consistent and correct. If using the SQL*Plus Instant Client make sure the SQL*Plus and Oracle libraries are from the same release. Make sure you have read access to the libraries.

To solve this error, you should set the Environment variable at session level open cmd or command prompt for windows as follows.

set ORACLE_SID=MSDB
set ORACLE_HOME=C:\app\product\11.2.0\db_1
set path=C:\app\product\11.2.0\db_1\bin

Run sqlplus again as follows.

sqlplus / as sysdba

Other case is as follows.

This error is related to the $ORA_TZFILE environment variable in Oracle 11GR2.

To solve this error, unset the variable and then call sqlplus again as follows.

$unset ORA_TZFILE

$sqlplus / as sysdba

OR

If you got this error on Windows operating system Oracle database, then open the command prompt as Administrator then try again.

Do you want to learn Oracle Database for Beginners, then read the following articles.

Oracle Tutorial | Oracle Database Tutorials for Beginners ( Junior Oracle DBA )