[INS-20802] Oracle Net Configuration Assistant failed.

During the installation of SES, you may come across an error “[INS-20802] Oracle Net Configuration Assistant failed.”

This error is due to conflict between a declared environment variable and a configuration value provided during the installation. The variable usually causing this is “ORACLE_HOME”

You can get further details of this issue from the log file located at

C:\Program Files\Oracle\Inventory\logs\installActionsyyyy-mm-dd_hh-mm-ss*.log

Further Details

Go to the bottom of the log file and you will see messages like

WARNING: oracle.net.ca.NetCAFatalException: Environmental error detected: Oracle Home is set to "D:\Oracle\product\11.2.0\sesdb_1" in the environment is different from Oracle Net Configuration Assistant installed Oracle Home.
WARNING: Verify that the ORACLE_HOME environment variable or registry setting is set to correct value and relaunch Oracle Net Configuration Assistant.
WARNING:
WARNING: at oracle.net.ca.NetCALogger.getOracleHome(NetCALogger.java:236)
WARNING: at oracle.net.ca.NetCALogger.initOracleParameters(NetCALogger.java:215)
WARNING: at oracle.net.ca.NetCALogger.initLogger(NetCALogger.java:130)
WARNING: at oracle.net.ca.NetCA.main(NetCA.java:427)
INFO:

INFO: Error: Environmental error detected: Oracle Home is set to "D:\Oracle\product\11.2.0\sesdb_1" in the environment is different from Oracle Net Configuration Assistant installed Oracle Home.
INFO: Verify that the ORACLE_HOME environment variable or registry setting is set to correct value and relaunch Oracle Net Configuration Assistant.
INFO:
INFO: Oracle Net Services configuration failed. The exit code is 1
INFO:
WARNING:
INFO: Completed Plugin named: Oracle Net Configuration Assistant

Resolution

Delete the Environment Variable “ORACLE_HOME” and you can do a Retry, but most likely the installation wizard will continue to throw the same error. The best option to to deinstall Oracle SES so that everything is clean again. Try to install it again.