I am experiencing the error message "unable to read file" when opening an excel file that I use regularly. I have been making duplicates of this file in separate workbooks and also "saving as" a different filename but now whenever I go to open the saved / used file again I get this message. On Clicking OK, the next message goes on to say that Excel found unreadable content in file xyz and asks if i want to recover the contents of that workbook. Clicking Yes to this prompts a new message that says "Damage to the file was so extensive that repairs were not possible. Excel attempted to recover your formulas & values, but some data may have been lost or corrupted" When I close this window I can then access the original file except that all the formatting & formulas have been lost. My computer has up to date antivirus programmes etc and I have only encountered this problen in the last week. Any assistance would be much appreciated.