Just so other people might understand what this is about, the relevant file comes from the homepage at
aphasia.talkbank.org. It is true that different versions of Excel behave differently. I am using Excel 16.45 on Mac under Big Sur and that file opens directly for me with no warnings. So, I don’t know whether there is any issue about old vs. new versions of the Excel program, or Mac vs. Windows, or different versions of the Excel file format. As far as I can see, the version of the file on the web is pretty generally compatible with most versions of Excel. If other people are having trouble opening Excel files, perhaps we could try to figure out exactly which versions fail when.