File signature analysis fails to recognize .old file

My friend May she found a strange file called "bkp.old" as below in the evidence files. She decided to use forensic tools to take a look at it and figure it out what's going on.

FTK said that it's an unknown file. But May was not satistify with this answer.

May used EnCase to conduct a file signature analysis on this evidence. Guess what? The signature analysis result was "Match". The file type was "Old Configuration Settings (ASCII)". May refused to believe it. That's too ridiculous!!!

May took a look at it's file header and compared with "File Type Signature Search.txt" . That's it. It's a Symantec Ghost Image file.

The suspect changed its ext name and bkp.gho became bkp.old. But to May's surprise forensic tools could not recognize this file correctly~ I taught May how to verify the file signature of a file. The verify result is as below.

Also I taught May how to mount a gho file and see what's inside this gho file. She did find some important files in this gho file and she exported those files to take a further examination.