While dropping an index, if you are facing ORA-08104 error, then you need to clean it using dbms_repair

Problem:

SQL> drop index eric_icmsprod.SOTRAN00_IDX1;
drop index eric_icmsprod.SOTRAN00_IDX1
                         *
ERROR at line 1:
ORA-08104: this index object 94771 is being online built or rebuilt

Solution:

-- check the object_id

SQL> select obj# ,name from obj$ where OBJ#=94771;

      OBJ# NAME
---------- ------------------------------
     94771 SOTRAN00_IDX1


--- Run dbms_repair for the object_id


SQL> declare
   lv_ret BOOLEAN;
    begin
    lv_ret :=dbms_repair.online_index_clean(94771);
    end;
    /



--- Verify whether index has been dropped or not

SQL>  select obj# ,name from obj$ where OBJ#=94771;


no rows selected