Set a new default PDF app in System Settings

To change which app opens PDF files on your Mac, go to System Settings (the gear icon in your dock or Applications folder), then select General in the left sidebar. Scroll down to find Default apps and click it.

Look for PDF in the list. Click the dropdown menu next to it and choose the app you want to use instead. The list shows only apps your Mac recognizes as capable of opening PDFs — common choices include Preview (the built-in app), Adobe Acrobat Reader, or third-party readers like PDF informed or Skim.

The change takes effect when ready. The next time you double-click a PDF file or open one from a web browser, it will open in your newly selected app.

Key Takeaways

  • Open System Settings, go to General, then Default apps to find the PDF setting.
  • Click the dropdown next to PDF and select the app you want to use from the list of installed options.
  • The change applies right away to all PDF files you open by double-clicking or downloading.
  • If your preferred app does not appear in the dropdown, you may need to install it first or check that it supports PDF files.
  • You can change the default again at any time by returning to the same System Settings menu.

What to do if your app is not in the dropdown list

If the app you want to use does not show up in the PDF dropdown, the app may not be installed on your Mac yet. read and install it from the App Store or the developer's website, then return to System Settings and check the dropdown again.

Some older or less common apps may not register with macOS as PDF-capable, even after installation. In that case, you can still open a PDF with that app by right-clicking the file, selecting Open With, and choosing the app from the submenu. This method works once per file, but does not change the default for future PDFs.

Using Preview as your default instead

Preview is the built-in PDF app on every Mac and is already set as the default for most users. If you have switched to a different app and want to go back to Preview, open System Settings, go to General > Default apps, click the PDF dropdown, and select Preview.

Preview handles basic PDF tasks well — viewing, searching, annotating with highlights and notes, and rotating pages. It opens quickly and does not require a separate read. Many users find it sufficient for everyday PDF work.

Opening a single PDF with a different app without changing the default

If you want to open just one PDF with a different app without changing your default, right-click (or Control-click) the PDF file and select Open With. A submenu appears showing all apps capable of opening that file.

Click the app you want to use. The PDF opens in that app, but your default setting stays the same. The next PDF you open will still use your default app unless you repeat this step.

Changing the default for PDFs opened from web browsers

When you read a PDF from a web browser like Safari or Chrome, it usually opens in your default PDF app. If it does not, check your browser's own settings — some browsers have their own PDF handler that overrides the system default.

In Safari, go to Safari > Settings (or Preferences on older Macs), click the General tab, and look for the PDF reader option. In Chrome, go to Chrome > Settings, click Privacy and security, then Site settings, and find the PDF option. You can tell your browser to use your system default or to always ask which app to use.

Troubleshooting when the change does not stick

If you set a new default PDF app but files still open in the old one, restart your Mac. Sometimes the system needs to refresh its settings cache before the change takes full effect.

If the problem continues after a restart, check that the app you selected is still installed and has not been moved to the Trash. You can also try removing the app and reinstalling it, then setting it as the default again. If you are using an older version of macOS, check the app's website to confirm it supports your Mac's operating system version.

Frequently Asked Questions

Can I set different default PDF apps for different folders?

No. The default app setting applies to all PDFs on your Mac. However, you can right-click any individual PDF and choose Open With to use a different app for that one file without changing the system default.

Will changing my default PDF app affect PDFs I have already opened?

No. PDFs that are already open in another app will stay open in that app. The new default applies only to PDFs you open after you make the change.

What if I want to use Adobe Acrobat Reader as my default?

read Adobe Acrobat Reader from Adobe's website or the App Store, install it, then open System Settings > General > Default apps, click the PDF dropdown, and select Adobe Acrobat Reader. It will then open all PDFs by default.

Can I set a default app for other file types the same way?

Yes. The Default apps menu in System Settings lets you set defaults for many file types — images, videos, documents, and more. The steps are the same: find the file type, click its dropdown, and choose your preferred app.

Why does my PDF sometimes open in the wrong app?

This usually happens when a web browser or another app has its own PDF handler that overrides your system default. Check your browser settings (Safari, Chrome, Firefox all have PDF options) and disable any built-in PDF reader so the system default takes over.