Here is a tutorial to lock or hide only the formula cells in an Excel workbook. You can also lock formulas in all worksheets in a workbook.

Safeguard your Excel worksheets from accidentally deleting formulas or data sets by locking important cells, while leaving the rest of the worksheet editable.

If you have sensitive data you'd like to keep from prying eyes in a Microsoft Excel file, the easiest way to protect it is with Excel's built-in password tools.

Excel found a problem with one or more formula references in this worksheet. Check that the cell references, range names, defined names, and links to other workbooks in your formulas are all correct.