An Excel file sent to me used a YMD date format.
Since then, all my old and new Excel files default to the YMD format.
Selecting a cell, a cell range, or a column, and then
DataText to ColumnsNextNextGeneral/Text/Date = MDY (or any other date
format selection) Finish has *no*effect. No changes are made to the file,
and going back to DataText to Columns... shows the data format to still be
YMD!

FormatCellsDate & choose any format has no effect either.

Did I get an infection from the worksheet that was sent to me?

How can I get back to the MDY date format?

I need a generalized solution since I have many worksheets in each of
several workbooks that are affected.