How to Change Default Applications for Web, Mail, and Media in Ubuntu

Ubuntu comes pre-configured with standard GNOME default applications—such as Mozilla Firefox for web browsing, Thunderbird for email, Videos (Totem) for media playback, and Rhythmbox for music. When you install alternative everyday software such as Google Chrome, Brave, VLC media player, or VS Code, Ubuntu might continue opening links and media files in its original applications. Configuring your preferred default programs ensures that clicking a URL in chat or double-clicking a video file opens your chosen software every single time.

Method 1: Configure System-Wide Defaults via Ubuntu Settings

The central Settings panel handles major application categories across your entire system:

1. Click on the Quick Settings menu in the top-right corner of the Ubuntu panel and select the Settings gear icon (or press the Super key and search for Settings).
2. Scroll down the left navigation sidebar and click on Apps.
3. Click on Default Apps at the top of the panel.
4. You will see a list of core system categories:
   • Web: Select your preferred browser (e.g., Google Chrome, Brave, or Firefox).
   • Mail: Choose your email client (e.g., Thunderbird or web app wrappers).
   • Calendar: Set your scheduling app.
   • Music: Choose your preferred audio player.
   • Video: Select your media player (such as VLC Media Player).
   • Photos: Set your image viewer.
5. Click the dropdown next to any category and select your installed application. The change applies immediately.

Method 2: Set Default Apps for Specific File Types via File Properties

If you want specific file extensions (such as .mkv videos, .pdf documents, or .csv spreadsheets) to open in a dedicated app:

1. Open the Files (Nautilus) file manager.
2. Locate a file with the specific extension you want to reassign.
3. Right-click the file and select Properties from the context menu.
4. Switch to the Open With tab at the top of the dialogue box.
5. Review the list of compatible applications. Select your desired application from the list.
6. Click the green Set as default button in the bottom-right corner.
7. From that moment on, double-clicking any file with that specific format will launch your chosen application.

Method 3: Resetting or Verifying via Terminal (MIME Types)

For users who prefer command line validation, Ubuntu tracks file associations using standard XDG MIME types. You can query your default browser by running:

xdg-settings get default-web-browser

And set Google Chrome as default with a single command:

xdg-settings set default-web-browser google-chrome.desktop