Default Oracle Home in Windows

In Oracle Universal Installer and OPatch User’s Guide it is documented that The first Oracle home is named the “DEFAULT_HOME” and registers itself in the Windows NT Registry.

Remember, NT means New Technology 🙂

There is apparently a Home Selector that is a part of the installation software, maybe something like D:\oracle\product\11.2.0\client_1\bin\selecthome.bat. Sometimes. Not sure

But there is no DEFAULT HOME in the registry.



Name                           Property
----                           --------
KEY_agent12c1                  ORACLE_HOME       : D:/oracle\core\
                               ORACLE_HOME_NAME  : agent12c1
                               ORACLE_GROUP_NAME : Oracle - agent12c1
                               NLS_LANG          : AMERICAN_AMERICA.WE8MSWIN1252
KEY_oracle_sysman_db_12_1_0_2_ ORACLE_HOME       : D:\oracle\plugins\oracle.sysman.db.discovery.plugin_12.
0_discovery_Home0              ORACLE_HOME_NAME  : oracle_sysman_db_12_1_0_2_0_discovery_Home0
                               ORACLE_GROUP_NAME : Oracle - oracle_sysman_db_12_1_0_2_0_discovery_Home0
KEY_oracle_sysman_emas_12_1_0_ ORACLE_HOME       : D:\oracle\plugins\oracle.sysman.emas.discovery.plugin_12.
2_0_discovery_Home0            ORACLE_HOME_NAME  : oracle_sysman_emas_12_1_0_2_0_discovery_Home0
                               ORACLE_GROUP_NAME : Oracle - oracle_sysman_emas_12_1_0_2_0_discovery_Home0
KEY_oracle_sysman_oh_12_1_0_1_ ORACLE_HOME       : D:\oracle\plugins\oracle.sysman.oh.agent.plugin_12.
0_agent_Home0                  ORACLE_HOME_NAME  : oracle_sysman_oh_12_1_0_1_0_agent_Home0
                               ORACLE_GROUP_NAME : Oracle - oracle_sysman_oh_12_1_0_1_0_agent_Home0
KEY_oracle_sysman_oh_12_1_0_1_ ORACLE_HOME       : D:\oracle\plugins\oracle.sysman.oh.discovery.plugin_12.
0_discovery_Home0              ORACLE_HOME_NAME  : oracle_sysman_oh_12_1_0_1_0_discovery_Home0
                               ORACLE_GROUP_NAME : Oracle - oracle_sysman_oh_12_1_0_1_0_discovery_Home0
KEY_OraClient11g_home1         ORACLE_HOME        : D:\oracle\product\11.2.0\client_1
                               ORACLE_HOME_NAME   : OraClient11g_home1
                               ORACLE_GROUP_NAME  : Oracle - OraClient11g_home1
                               ORACLE_BUNDLE_NAME : Enterprise
                               NLS_LANG           : AMERICAN_AMERICA.WE8MSWIN1252
                               OLEDB              : D:\oracle\product\11.2.0\client_1\oledb\mesg
                               ORACLE_HOME_KEY    : SOFTWARE\ORACLE\KEY_OraClient11g_home1
                               MSHELP_TOOLS       : D:\oracle\product\11.2.0\client_1\MSHELP
                               SQLPATH            : D:\oracle\product\11.2.0\client_1\dbs
KEY_OraGtw11g_home1            ORACLE_HOME        : D:\oracle\product\11.2.0\tg_1
                               ORACLE_HOME_NAME   : OraGtw11g_home1
                               ORACLE_GROUP_NAME  : Oracle - OraGtw11g_home1
                               NLS_LANG           : AMERICAN_AMERICA.WE8MSWIN1252
                               ORACLE_BUNDLE_NAME : Enterprise
                               MSHELP_TOOLS       : D:\oracle\product\11.2.0\tg_1\MSHELP
                               SQLPATH            : D:\oracle\product\11.2.0\tg_1\dbs
                               ORACLE_HOME_KEY    : SOFTWARE\ORACLE\KEY_OraGtw11g_home1
KEY_sbin12c1                   ORACLE_HOME       : D:\oracle\sbin
                               ORACLE_HOME_NAME  : sbin12c1
                               ORACLE_GROUP_NAME : Oracle - sbin12c1
remexecservicectr              remaining_time : 120000

How do I set my Oracle Home?

Actually if you enter a command like “lsnrctl start”, the OS will search in the PATH for lsnrctl and determines the Oracle Home name accordingly.

Therefore, the only thing you must do to change your default Oracle Home is to set the PATH environment variable. Only then your LSNRCTL START will find the right binary and right parameter file to start your listener.

3 Replies to “Default Oracle Home in Windows”

  1. Hi Laurent,

    Precisely, this is how Oracle set the Oracle Home (and other environment): it checks for the oracle.key in the same directory as the executable (or .dll) that is called and that file has the registry key to get all environment.


  2. Thanks Franck for this valueable info, I did never notice the oracle.key !
    documented in Note 73963.1
    How it Works
    Everything is based upon the BIN directory from which an executable is

    Oracle knows from which BIN directory a particular executable has been
    started and searches in this BIN directory for a file named oracle.key.
    In this file Oracle finds the reference to the environment it should use
    e.g. SOFTWARE\ORACLE\HOME1. If the oracle.key file is not present, then
    the Default Oracle Home is used. This is the case for Non-Multiple Oracle
    Home products.

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