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Local SQL*Plus Connection failing with ORA-12560: TNS:protocol adapter error (Doc ID 2531667.1)

Last updated on APRIL 22, 2019

Applies to:

Oracle Database - Enterprise Edition - Version 10.1.0.2 and later
Information in this document applies to any platform.

Symptoms

sqlplus / as sysdba (Bequeath) or connecting using other non-sysdba users is failing with ORA-12560: TNS:protocol adapter error

Enter user-name: sys as sysdba
Enter password:
ERROR:
ORA-12560: TNS:protocol adapter error

Changes

 There are several changes which can lead to this error. Below are few of the them 

Cause

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In this Document
Symptoms
Changes
Cause
Solution
 Database on UNIX platforms:
 1. Binaries corruption: 
 2. Security products:
 3. Environment variables:
 Database on WINDOWS platforms: 
 1. Environment Variables:
 2.  Failed upgrade or any changes.
 3. Service is not started.
 4.  Recreate the OracleService<SID>.
 5. Other issues
References

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