"We can't open this workbook. It's set to only show certain named items, but they aren't in the workbook" when previewing a spreadsheet and blank worksheet when I edit

Issue
When I try to preview a spreadsheet I get the error

"We can't open this workbook. It's set to only show certain named items, but they aren't in the workbook".

When I edit the spreadsheet, it just displays as a blank worksheet.

Cause
The worksheet(s) have been hidden in Excel.

Solution

1. In FYI, edit the spreadsheet.
2. In Excel, from the View menu option, click Unhide
3. A pop-up message displays to confirm the Unhide. Click OK.
   This should show the content of the spreadsheet.
4. Close the spreadsheet and click "I'm finished Editing" in FYI.
5. Try to Preview and Edit the spreadsheet again.