Something wrong with EnCase index search in Unallocated area

hi,

My EnCase version is v7 and I found a terrible issue about index search in Unallocated area. Without Internet Evidence Finder I could not the truth of EnCase index search...Thanks God I use IEF to carve the evidence file and some webmail found..so I export those records as below Excel datasheet..guess what? I did index the evidence file and search same Simplified Chinese keywords  in the Excel datasheet..no any hits found...

Forensics is a strict science..such kind of mistakes are unacceptable..Guidence should think highly of Chinese market and do something to fix this issue as soon as possible...