Default apps are the programs your device automatically opens when you click a file or link

A default app is the program your computer or phone launches without asking you which one to use. When you click a PDF, your system opens it in whatever PDF reader you set as the default. When you click an email address, it opens in your default email client. When you click a web link, it opens in your default browser. You set these defaults yourself — your device does not choose them for you.

The reason defaults exist is speed. If your system asked you every time which program to use, opening files would be slow and annoying. Instead, you choose once, and your device remembers. If you later want to use a different program for that file type, you change the default and your device remembers the new choice.

Different file types can have different defaults. You might set Chrome as your default browser but Firefox as your default for downloading PDFs. You might set Outlook as your default email client but still open calendar files in Google Calendar. Each file type — or each link type — can point to a different program.

Key Takeaways

  • Default apps are the programs your device automatically opens for specific file types or links, without asking you each time.
  • You set defaults yourself through your system settings, and you can change them at any time.
  • Different file types can have different defaults — your browser default does not have to match your email default.
  • If a file opens in the wrong program, changing the default will fix it for all future files of that type.
  • Some programs automatically set themselves as defaults when you install them, which you can override in settings.

How defaults work on Windows

On Windows, you set defaults through the Settings app under Apps > Default Apps. You can search for a specific file type — like .docx or .jpg — and see which program opens it. You can also choose a default for broader categories like "Web browser", "Email client", or "Photo viewer".

When you install a new program, it may ask permission to become the default for files it can open. You can say yes or no. If you say yes and later change your mind, you can go back to Settings and pick a different program. Windows remembers your choice until you change it again.

Some programs are harder to change than others. Your default browser, for example, is a system-level choice that affects all programs on your computer. Your default email client works the same way. Other defaults — like which program opens image files — are easier to override on a case-by-case basis if you want to.

How defaults work on Mac

On Mac, you set defaults through System Settings under General > Default Web Browser and General > Default Email Client. For other file types, you right-click the file, select "Open With", choose the program you want, and then click "Always Open With". Mac will remember that choice for all files of that type going forward.

You can also change defaults by opening a file with a different program than usual. Right-click the file, choose "Open With", pick a program, and select "Always Open With" — that program becomes the new default for that file type. If you later want to switch back, repeat the process with a different program.

Some Mac programs set themselves as defaults during installation. You can override this in System Settings or by using the "Open With" method above. Unlike Windows, Mac does not have a single Settings page where you can see all your defaults at once — you change them one file type at a time.

Why programs change your defaults without asking

When you install a new browser, email client, or media player, the installer often asks whether you want to make it the default. If you click "Yes" or just proceed without reading, that program becomes your default for its file type. Some programs set themselves as default even if you do not explicitly agree — they ask for permission during installation in small text you might miss.

This happens because programs want to be the one you use. A browser maker wants you to use their browser for all your web browsing. An email client wants to be your default email program. They are not being sneaky — they are asking — but the request is straightforward to miss or misunderstand.

If a program changed your defaults and you did not want it to, you can change them back. Go to your Settings (Windows) or System Settings (Mac), find the default for that file type, and pick the program you actually want. Your choice will stick until you change it again.

What happens when you do not have a default set

If no default is set for a file type, your system will ask you which program to use when you click that file. A dialog box appears with a list of programs that can open it. You pick one, and your system may ask whether you want to use that program every time, or just this once.

This is rare on Windows and Mac because both systems come with defaults already set for common file types — browsers for web links, text editors for .txt files, and so on. But if you delete a program or if a file type is unusual, you might see this dialog.

If you see it and want to avoid it in the future, pick the program you want and select the option to always use it. That program becomes your new default for that file type.

When to change your defaults

Change your default if a file type keeps opening in the wrong program. If PDFs open in a program you do not like, change the default to a PDF reader you prefer. If web links open in a browser you do not use, change your default browser. If email addresses open in an email client you do not have set up, change your default email client.

You might also change defaults if you install a new program you like better. If you switch from Chrome to Firefox, change your default browser to Firefox. If you switch from Outlook to Gmail, change your default email client. Your system will then use the new program for all future files and links of that type.

Changing a default does not uninstall the old program or delete any files. It just tells your system which program to use when you click a file. You can still open files in other programs manually if you want — changing the default just changes what happens when you click.

Default apps for different file types

Your system can have different defaults for different file types. Here are the most common ones you might change:

  • Web browser: Opens when you click a web link (http or https). Examples: Chrome, Firefox, Safari, Edge.
  • Email client: Opens when you click an email address (mailto: link). Examples: Outlook, Gmail, Apple Mail, Thunderbird.
  • PDF reader: Opens PDF files. Examples: Adobe Reader, Preview (Mac), Microsoft Edge.
  • Image viewer: Opens image files like .jpg, .png, .gif. Examples: Photos (Windows), Preview (Mac), Photoshop.
  • Text editor: Opens plain text files like .txt. Examples: Notepad (Windows), TextEdit (Mac), VS Code.
  • Media player: Opens audio and video files. Examples: Windows Media Player, VLC, QuickTime (Mac).
  • Document editor: Opens Word documents, spreadsheets, and presentations. Examples: Microsoft Office, Google Docs, LibreOffice.

You do not have to use the same program for everything. You can set Chrome as your browser, Outlook as your email, and VLC as your media player. Each default works independently.

Frequently Asked Questions

Can I open a file in a different program without changing the default?

Yes. Right-click the file and select "Open With" (Windows) or "Open With" (Mac), then pick the program you want. This opens the file in that program without changing your default. The next time you click a file of that type, it will still open in your default program.

What if I change my default and then change my mind?

Go back to your Settings (Windows) or System Settings (Mac) and change the default again. You can switch back and forth as many times as you want. Your system will use whatever default you set most recently.

Do I need to set a default for every file type?

No. Your system comes with defaults already set for common file types. You only need to change them if a file type opens in a program you do not like, or if you install a new program you prefer.

Why did my default change when I installed a new program?

Many programs ask to become your default during installation. If you clicked "Yes" or proceeded without reading the installer carefully, that program became your default. You can change it back in your Settings at any time.

Can I set different defaults for the same file type on different occasions?

No. A default is system-wide — once you set it, that program opens all files of that type. But you can always right-click a specific file and choose "Open With" to use a different program just that once, without changing your default.