Just made another recommendation that someone use LibreOffice Calc to fix a possibly corrupted Excel workbook. Dunno whether anyone reads anything in Tips and Tutorials, but it might be useful to add a sticky topic directing users to use LibreOffice to open Excel workbooks which Excel itself either can't or takes an inordinately long time to do so. IMO, better to suggest portable versions of LibreOffice, such as found at https://www.libreoffice.org/download/portable-versions/ .

In my experience, LibreOffice can open a wider variety of .XLS and .XLS[XMB] files than Excel itself can.