I have just done something incredibly stupid and hope that someone may have a solution. I have been working on a spreadsheet for the past 4 hours and saving regularly. As I saved, the following message popped up: "Some content in Name.xls may not be saved because it is not compatible with the Excel 97-2004 Workbook (.xls) file format. Do you still want to save the workbook in this format? To save the workbook in a new format and preserve all content, click No, and then on the Format pop-up menu, click Excel Workbook (.xlsx). To save the workbook in the current format and remove all incompatible content, click Yes." Somehow I managed to not read the popup properly and just went ahead and saved (clicked "yes"). I then closed the spreadsheet and now all the work from the past 4 hours is gone. Is there any way to recover it? Thanks so much!