1. Add the file to a trusted location An easy way to open a file is to add it to Excel's Trusted Locations . When you add a file or folder to Trusted Locations , that file or folder is considered safe ...

If your XLSX file isn’t opening in Excel, you might not have Excel 2007 or a later version, which is needed for XLSX compatibility. Ensure your Microsoft Excel is updated.

Solution 7: Open MS Excel in Safe Mode Solving the “ Excel cannot open because the file format is not valid ” problem can sometimes be as simple as booting your computer into Safe Mode . This is ...