I received this error on a MacBook, when trying to connect with SQL*Plus to my database:
SQL*Plus: Release 188.8.131.52.0 Production on Mon Nov 21 08:27:22 2016 Copyright (c) 1982, 2016, Oracle. All rights reserved. ERROR: ORA-21561: OID generation failed
The issue comes from not having the MacBook’s hostname associated with the home IP address. To fix this, simply find your hostname:
~$ hostname MY_MACBOOK
Then edit your /etc/hosts file and add the home name to the home IP address:
127.0.0.1 localhost MY_MACBOOK
Also make sure that when you edit the hosts file, that you are not connected to a VPN. Some VPN clients may overwrite the hosts file.