I have a customer running Excel 2013. She download spreadsheets from her payroll company. When she tries to open the spreadsheet it opens but no data displays. No error. No data. They are .xls (not .xlsx).
I copy the spreadsheet to my computer (Excel 2016) and it opens with the warning "The file format and extension of <filename.xls> don't match, The file could be corrupt. Do you want to open it anyway?" (she said this is normal). I say yes and it opens.
Here is the weird part. As long as I copy the spreadsheet to my computer (I don't even have to open it) and copy it back she can then open it. I don't do anything to it. Just copy it to my computer and turn right around and copy it back. Then she can open it.
She can open all her other spreadsheets just fine (.xlsx). Just not these until I copy them to my computer and copy them back.....