ORA-12560: TNS:protocol adapter error

Few “years” back, while it was almost impossible to install Oracle 10g on Windows 7/8, I made some attempts & managed to install 32Bit versions of 10g 10.2.0.3.x successfully. A particular release 10.2.0.4 had helluva of issues, mainly TNS related & I can see many visits to that thread even today! I believe, those visitors are not coming over there for 10g, instead for TNS.

On Windows, the below is a typical situation & we’ll see the primary reasons for the same.

Microsoft Windows [Version 10.0.22000.556]
(c) Microsoft Corporation. All rights reserved.

C:\Windows\system32>sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Mon Mar 21 07:59:29 2022
Version 19.11.0.0.0

Copyright (c) 1982, 2020, Oracle.  All rights reserved.

ERROR:
ORA-12560: TNS:protocol adapter error


Enter user-name:

On Windows, everything is another service. So we’ll start with checking whether the “Oracle” service for the database instance has started.

I’m using Oracle database on my laptop mostly for learning purposes, hence the service startup is set as “Manual”. This gives me control over the resources consumed by the database. Not just the service, I have setup the instance to start manual to insure Oracle service doesn’t open the database automatically. Latest Windows OS that use quick boot will save the state of the service, hence you might find your database readily available once after a reboot, although you set everything as manual :)

Let’s see what happens after starting the “Oracle Service”.

Well, that fixes one of the many reasons for the dreaded ORA-12560: TNS:protocol adapter error! As soon I am hit with another, will amend this post.