How to unlock XLSX file

Sheetize XLSX Unlocker for .NET provides a simple yet powerful API for removing password protection from an Excel Open XML workbook while preserving all worksheets, charts and formatting. This is useful when you need to access a secured file for further processing, analysis or redistribution in pipelines that require an unlocked version.

Main Features

Unlock password‑protected XLSX

Decrypt an existing XLSX file with the correct password. The operation restores full editability of the workbook.

Preserve formatting & objects

All cell styles, formulae, tables, charts and images remain intact after unlocking.

Streaming support

Unlock large workbooks in a streaming fashion to keep memory usage low, ideal for batch processing of many files.

Detailed Instructions

XLSX unlock workflow

To unlock an XLSX file with Sheetize, follow these steps:

  1. Initialise the Unlocker: Create an instance of SpreadsheetUnlocker.
  2. Configure options: Set UnlockerLoadOptions with the source file path and the required password.
  3. Define output path: Provide the destination path where the unlocked workbook will be saved.
  4. Execute unlock: Call Process with the prepared load and save options.

Example – Unlock an XLSX file with a password

using Sheetize;
var loadOptions = new UnlockerLoadOptions
{
    InputFile = "Protected_report.xlsx",
    Password = "MySecretPwd"
};
var saveOptions = new SaveOptions
{
    OutputFile = @"E:\\Unlocked_report.xlsx"
};
SpreadsheetUnlocker.Process(loadOptions, saveOptions);

Example – Unlock an XLSX file with a write‑protection password

using Sheetize;
var loadOptions = new UnlockerLoadOptions
{
    InputFile = "Protected_report.xlsx",
    PasswordOfWriteProtection = "WritePwd"
};
var saveOptions = new SaveOptions
{
    OutputFile = @"E:\\Unlocked_write_protected.xlsx"
};
SpreadsheetUnlocker.Process(loadOptions, saveOptions);

Expanded Format Support

  • Sheetize can also unlock password‑protected CSV, TSV and HTML exports generated from a workbook (the resulting files are unwrapped from the encrypted ZIP container).

With these capabilities, Sheetize makes XLSX unlocking effortless, whether you need a quick one‑off script or a production‑grade service that processes thousands of protected spreadsheets daily.

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