Please ensure the .xls file is not opened in other workbooks, add-ins, or apps. After coming to that conclusion, simply attempt to open the file again in Excel to see if the problem no longer exists.

If Microsoft Excel fails to recognize a file in the XLSX or XLS format, the data contained in the file could be corrupted. When you open a corrupted workbook in Excel, the program should ...

An Excel file may be inaccessible due to a disk or network error, even though it isn't corrupted. In such cases, Excel won't be able to repair the file because the issue isn't with the file itself.

Microsoft Excel has an import wizard, but if you structure the text correctly, you can bypass the wizard altogether.

How to Open an XLSM File. An XLSM file is a spreadsheet that contains macros written in the Visual Basic for Applications, or VBA, language. Macros enable you to automate repetitive tasks and save ...

If you can't open a file on your computer, don't give up right away. These tricks will give you a fighting chance of accessing or recovering its contents.