I like to spend time with Oracle DB just as much time I spend with SQL Server, but we exclusively use SQL Server at our work so I am not getting enough time with Oracle anymore. And another reason is it with Oracle there are way too many variable to consider when you are troubleshooting something. So when couple of days back when I boot up my VM of Oracle, I ran into this strange error and I was genuinely surprised to find how minute the cause could be.

So, this how the story goes …. after booting my VM, I started SQL PLUS utility (it is kind of SQLCMD equivalent of SQL Server, it is CLI to access Oracle DB to be exact). When I was asked to provide login credentials, when I provided ‘em I was greeted with following error message,


ORA-12560:  TNS: protocol adapter error



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