Bernard > If I read it correctly then a table whose number of blocks in PK > inferior to number of blocks reported in dba_Tables had endure > delete. Two remarks: 1) "number of block" should be "number of referenced blocks". 2) As Jonathan already wrote, with ASSM there could be non-initialized blocks below the HWM. In addition, with FSSM, since the HWM is increased by 5 blocks at time (except for the first 5 blocks and when _BUMP_HIGHWATER_MARK_COUNT has been set) you could have up to 5 empty blocks ***per segment and free list group*** which are not referenced by the index yet. HTH Chris -- //www.freelists.org/webpage/oracle-l