Well, I do hope I am worng but this is starting to sound like you need some auditing ASAP.

First of all, do you have ANYTHING in the SYSTEM tablespace that is not owned by SYS or SYSTEM?

Try this for starters.

select owner, segment_name, segment_type
from dba_segments
where tablespace_name='SYSTEM'
and owner not in ('SYS','SYSTEM')

And this one for indexes.

SELECT OWNER,INDEX_NAME
FROM DBA_INDEXES
WHERE TABLESPACE_NAME='SYSTEM'
AND OWNER NOT IN ('SYS','SYSTEM')

The only other user that should have objects in there is OUTLN.
If you have tables and indexes in the system tablespace you should re-build them to another tablespace ASAP.

Will you create a new tablespace for the re-build?
Will they be online?


Personally I like to spool a script for the rebuild and include these parameters in that re-build script...

Spool d:\Pxxx_index_rebuild.log
set echo on;

Blah blah blah

spool off;

This way you have a log of all the re-builds, if there are any errors you can always refer to the log and make adjustments.

MH