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File Access Setup

To open local Markdown files by double-clicking them, you need to enable file access for the extension.

Why is This Needed?

By default, Chrome extensions cannot access local files (file:// URLs) for security reasons. You need to explicitly grant this permission.

Enable File Access in Chrome

Step 1: Open Extensions Page

Navigate to chrome://extensions/ in your browser, or:

  1. Click the three-dot menu (⋮) in Chrome
  2. Go to More tools → Extensions

Step 2: Find Markdown Viewer

Scroll through your extensions or use the search box to find Markdown Viewer.

Step 3: Open Extension Details

Click “Details” on the Markdown Viewer card.

Step 4: Enable File Access

Find the option “Allow access to file URLs” and toggle it ON.

Enable file access toggle

✅ Done! You can now double-click .md files to open them in Chrome.

Enable File Access in Firefox

  1. Go to about:addons
  2. Find Markdown Viewer
  3. Click the extension
  4. Under Permissions, enable access to file URLs

Setting Chrome as Default for .md Files

Windows

  1. Right-click any .md file
  2. Select “Open with” → “Choose another app”
  3. Select Google Chrome
  4. Check “Always use this app to open .md files”
  5. Click OK

macOS

  1. Right-click any .md file
  2. Select “Get Info”
  3. Under “Open with”, select Google Chrome
  4. Click “Change All…“ to apply to all .md files

Linux

Depends on your desktop environment. Generally:

  1. Right-click the .md file
  2. Select “Properties” or “Open With”
  3. Choose Chrome/Chromium as the default application

Troubleshooting

Files Still Don’t Open?

  1. Verify the extension is enabled — Check chrome://extensions/
  2. Confirm file access is on — The toggle should be blue/enabled
  3. Restart Chrome — Close all Chrome windows and reopen
  4. Check file association — Make sure .md opens with Chrome

Security Considerations

Enabling file access means the extension can read local Markdown files. This is safe because:

  • ✅ Markdown Viewer only processes Markdown content
  • ✅ No data is sent to any server
  • ✅ All processing happens locally
  • ✅ The extension is open source and auditable

Alternative: Without File Access

If you prefer not to enable file access, you can still use Markdown Viewer:

Drag and Drop

  1. Open Chrome
  2. Drag your .md file into the browser window
  3. The file will be rendered

Use the Open Dialog

  1. Press Ctrl/Cmd + O in Chrome
  2. Navigate to your file
  3. Select and open it

Online Files Only

View Markdown files on:

  • GitHub
  • GitLab
  • Any website serving .md files

Next Steps

Now that file access is set up: