Siebel Installation Guide for UNIX: Servers, Mobile Web Clients, Tools > Configuring the RDBMS > Configuring Oracle for Siebel Applications >

Guidelines for Creating Temporary Oracle Table Spaces

All user temporary table space definitions should be modified from the default of SYSTEM to the name of the temporary table space; for example, TEMP or TEMP_TS. Otherwise, SORT operations interfere with Oracle dictionary management.

To find out which users are assigned to which temporary table spaces, query the TEMPORARY_TABLESPACE column of DBA_USERS, and if any users are assigned to a table space other than the one allocated for temporary sort-type operations, correct the situation.