LOB indexes corruption in Oracle Why is it not possible to rebuild corrupt LOB indexes? So if my LOB index is corrupted, how to recover it?
The alert log should tell you if a data block is corrupt, no need to validate index structure. That will lock your table until completed. If no backups you might try to exporting the data using expdp. Then drop the table and re-create it and import using impdp. You will need to create the indexes, constraints and grants as well. Could also use CTAS.