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Convert your first document

In this tutorial you will install Dangerzone, open a document you don't fully trust, and turn it into a safe PDF. By the end, you will know what the application looks like, where the safe file ends up, and what happens to the original.

You need a computer running macOS, Windows, or a supported Linux distribution, an internet connection for the installation, and a document to convert. Any PDF, office document, or image works. Dangerzone retains the original and processes it without network connection. If you have nothing at hand, a PDF you downloaded from the web is a fine candidate.

1. Install Dangerzone

Follow the installation guide for your platform, then come back here:

  • macOS (download the .dmg, or brew install --cask dangerzone if you use Homebrew)
  • Windows (download the .msi, or winget install FreedomofthePressFoundation.Dangerzone)
  • Ubuntu and Debian
  • Fedora

Qubes OS and Tails users can follow along as well, using the Qubes OS and Tails guides.

2. Start Dangerzone for the first time

Launch Dangerzone from your applications menu.

The first time it starts, Dangerzone needs a sandbox: that's where the actual documents will be opened, in a secure way. What you see depends on how you installed it:

  • On macOS and Windows, and with the dangerzone-full Linux packages, the sandbox is bundled. Dangerzone installs it and moves on.
  • With the slim dangerzone Linux packages, a dialog titled Download conversion sandbox? asks whether Dangerzone may download the sandbox from the internet. Click Yes, download sandbox and enable updates. The download is a few hundred megabytes.

If the sandbox was bundled, Dangerzone asks the same question on the second start instead, with a dialog titled Enable automatic sandbox updates?. Click Yes, enable sandbox updates so that Dangerzone keeps the sandbox up to date and tells you when a new Dangerzone release is out. You can change your mind later from the hamburger menu in the top-right corner. See update notifications for what this setting does and does not do.

The main window then shows a large Select suspicious documents ... button. On the first run, a status bar at the bottom of the window shows the startup tasks that Dangerzone is performing, mainly starting a VM on Windows/macOS systems and installing the container image. You can proceed with selecting a document while the startup tasks run in the background.

3. Choose the document

Click Select suspicious documents ... and pick your document. You can also drag and drop one or more files onto the window.

The window switches to the settings view. It shows how many documents you selected and a Change Selection button if you picked the wrong one.

4. Review the settings

Leave the defaults for this first conversion, and simply read what they do:

  • Save as shows the name of the output. The safe file gets the same name as the original with a -safe.pdf suffix, so report.docx becomes report-safe.pdf.
  • Move original documents to 'unsafe' subdirectory is selected. After the conversion, the original is moved into an unsafe/ folder next to the safe PDF, so that you don't open it by accident later.
  • Save safe PDFs to lets you pick another output folder instead.
  • Open safe documents after converting opens the result in your PDF viewer once it is ready. On Linux you can pick which viewer to use.
  • OCR document language is checked, with English selected. OCR (optical character recognition) reads the text in the page images and adds an invisible text layer to the safe PDF, so you can still search and copy text. It works best when it knows the language, so pick your document's language from the list if it isn't English.

5. Convert

Click Convert to Safe Document.

Dangerzone opens the document inside the sandbox, renders every page to raw pixels, then rebuilds a PDF from those pixels outside the sandbox. A progress bar shows each stage. A one-page PDF takes a few seconds. A long office document with OCR takes longer.

When it is done, the document row shows a green check mark, and your PDF viewer opens the safe PDF if you left that setting on.

6. Look at the result

Open the folder that contains the original document. You will find:

  • <name>-safe.pdf: the safe PDF. This is the file you can share, print, or keep.
  • unsafe/<name>: the original, moved out of the way.

Open the safe PDF and check that all pages are there and that you can select text. Because the PDF was rebuilt from pixels, links, forms, and embedded scripts from the original are gone. That is the point.

What you learned

You have installed Dangerzone, let it fetch its sandbox, and converted a document while keeping the original archived. Every later conversion follows the same three steps: select, review settings, convert.

Where to go next