I am facing a very weird problem. I have created a .xlsx file at excel 2007 and when I am trying to open it at newer versions of excel (tried 2010 and 2016) I get message that file is corrupted and repair removes much of my work in the file (conditional format formulas at half of sheets). The most weird is when I upload it at onedrive and work it at excel online in browser everything is fine but If I download it again I have the same problem. Any idea what is causing this?