I was copying and pasting some "Sum"s - Ctrl C & Ctrl V. Next thing I know one cell listing has disappeared from my Sum . well I guess I over wrote it when I was pasting, no problem Ctrl Z (undo). Nothing. again? nothing. again? nothing. hmm. Then I noticed that at the top of my page it now says "FileName" - Group
Anyone have any smart ideas what I may have done? and how I can resolve it? this is a very important and intensive file, which I would rather not have to resort back to a prior saving of if possible.