Create And Register CUSTOM Schema On EBS 12.2 A custom / read-only schema can be created in 12.2.x the same way as it has been done so far for the previous releases (11i / R12). The only difference in 12.2 is that the custom schema should also be registered with EBS or it has to be manually enabled for editions.  Else, ORA-38818 will be encountered. For example: create synonym [CUSTOM_SCHEMA].[OBJECT_NAME] for APPS.[OBJECT_NAME] * ERROR at line 1: ORA-38818: illegal reference to editioned object APPS.[OBJECT_NAME] The custom schema can be registered by the following APIs: 1. If Online Patching Enablement is not yet enabled (as suggested in ADZDPCUST.sql): SQL> exec FND_ORACLE_USER_PKG.LOAD_ROW('CUSTOM_SCHEMA', 'CUSTOM', 'INVALID', NULL, 'N', 'B');  2. If Online Patching Enablement has already been enabled: sqlplus SYSTEM SQL> alter session set current_schema=APPS; SQL> exec AD_ZD_PREP.ENABLE_CUSTOM_USER('CUSTOM_SCHEMA');