Anyway, theres multiple ways of storing data in a spreadsheet, can you please confirm what test step youre using? (Datasink? Groovy? Events?) Also when you say "it destroys the file", can you please clarify what you actually mean by this.....do you mean the file contents are deleted out of the file so it reverts to a zerobytes file? Just a bit more info to clarify would help a lot.
if this helped answer the post, could you please mark it as 'solved'? Also if you consider whether the title of your post is relevant? Perhaps if the post is solved, it might make sense to update the Subject header field of the post to something more descriptive? This will help people when searching for problems. Ta