My spreadsheets have suddenly started to change the date format. I am working in an office environment and when opening the spreadsheets on any other computer the dates entered are correct. I have checked the Excel options and placed a checkmark in the 1904 date settings. After closing it works for a new worksheet - but does not apply to Excel defaults or any existing spreadsheets (and we have thousands) EAch time I have to go in and reapply the checkmark for the 1904 date change - and it still doesn't apply to the entire spreadsheet. I have cleared the cell of all formats - tried reapplying a date format - and still once I type Apr 20 it changes to 1 Apr. HELP!!!