How to Open Xlsx in Excel 2003by Emmanuelle Douglas
Excel 2007 introduced the new xlsx format to the Office suite. Opening these files in Excel 2003 often gave users an error message until they downloaded the compatibility tool. Once the compatibility tool is downloaded, these files can be opened in Excel 2003. This compatibility tool is available for download from Microsoft's website and is free. The compatibility tool made it possible for all Office 2003 products to work with Office 2007 new file formats.
Access the Microsoft Downloads website. Type "Compatibility Tool" in the search box. Download the Compatibility Tool. Once it has downloaded to your computer, double click the execution file and follow the installation instructions. Click "OK" once the installation is complete.
Open Excel 2003 and locate an Excel 2007 workbook. Click "File" on the menu bar, then click "Open." Browse your files and locate the workbook. Click the workbook, then click "Open."
View the xlsx workbook in Excel 2003. You can work with this new format since the compatibility tool is installed.