How to unprotect a password protected Excel file in C#
Introduction
This C# recipe shows how you can unprotect a password protected Excel file and save it a as an unprotected file
Ingredients
The recipe uses the EPPlus library version 4.5.3.3. This is the last version of EPPlus under the LGPL License (aka free for commercial uses). You can install it using Nuget Package manager:
Install-Package EPPlus -Version 4.5.3.3
C# Code
var protectedFile = @"C:\Temp\ExcelRecipes\Password\protected.xlsx";
var unprotectedFile = @"C:\Temp\ExcelRecipes\Password\unprotected.xlsx";
// open protected file
using (ExcelPackage fileExcelFile = new ExcelPackage(new FileInfo(protectedFile), "secret123"))
{
// save as unprotected file
fileExcelFile.SaveAs(new FileInfo(unprotectedFile), "");
}