Allow to unprotect sheets from external application.
External application is unable to unprotect your worksheet, read formula, etc. If you are using locked spreadsheet from external application and need to allow this application full access to your workbook, you should use Project Options | Excel Object Model protection options ... | Allow external applications to access Object Model of locked workbook. This option requires Unlock Code to be passed to LockXLS Runtime to identify application, which can access your spreadsheet.
You can find more information and sample VBA code for this option here.
See Also