Readers help support Windows Report. We may get a commission if you buy through our links. One of the major causes of this problem is large Excel files. You may ...

XLS files are Excel workbook files created in Excel 97 or Excel 2003. The 2007, 2010 and 2013 versions of the program use the XLSX format by default to save workbooks, but can also use the XLS format.

If you launch multiple files by double-clicking their shortcut icons, or via the "Open" menu in Excel, the files will run simultaneously in one Excel window. In order to launch the files in their ...