orabase in 11g on Linux seems to get ORACLE_BASE from $ORACLE_HOME/inventory/ContentsXML/oraclehomeproperties.xml. But that file in 10g does not have the PROPERTY_LIST section: <PROPERTY_LIST> <PROPERTY NAME="ARCHITECTURE" VAL="64"/> <PROPERTY NAME="ORACLE_BASE" VAL="/u01/app/oracle"/> </PROPERTY_LIST> So if it existed for 10g, it would have to work some other way. On Windows, it works differently. My C:\oracle\product\10.2.0\db_1\inventory\ContentsXML\oraclehomeproperties.xml file does not have that section either. But orabase.exe on a remotely mapped z: drive on a server running 11g reports ORACLE_BASE on my local 10g database successfully: C:\temp>Z:\oracle\product\11.1.0\db\BIN\orabase Oracle home environment variable not set C:\temp>set oracle_home=C:\oracle\product\10.2.0\db_1 C:\temp>Z:\oracle\product\11.1.0\db\BIN\orabase C:\oracle\product\10.2.0 It checks %oracle_home%\nls\data: C:\temp>set oracle_home=C:\temp C:\temp>Z:\oracle\product\11.1.0\db\BIN\orabase Failed to verify status of C:\temp\nls\data. Error returned is 2 C:\temp\nls\data does not exist. Specify a valid Oracle Home location Yong Huang -- //www.freelists.org/webpage/oracle-l