Set a new default PDF app in three steps

To change which app opens PDFs on your Mac, right-click any PDF file, select "Open With", choose the app you want, then click "Change All". That single action changes the default for every PDF on your computer. If you want to change it back later, the same process works with any other app.

The "Change All" button is the key — without it, you're only opening that one file in a different app, not changing the default. Once you click it, macOS remembers your choice and uses that app every time you double-click a PDF.

Key Takeaways

  • Right-click a PDF file, select "Open With", pick your preferred app, and click "Change All" to set it as the default for all PDFs.
  • Preview is the built-in Mac PDF app; other common choices include Adobe Acrobat Reader, PDF Expert, and web browsers like Chrome or Safari.
  • Changing the default only affects how PDFs open when you double-click them — it does not change how they open from links in emails or web pages.
  • You can set different defaults for different file types, so your PDFs might open in one app while Word documents open in another.

The step-by-step process

Open Finder and locate any PDF file on your Mac. Right-click it (or Control-click if you have a single-button mouse) and a menu will appear. Look for "Open With" — it will show a submenu with several app options.

The apps listed are ones macOS thinks can open PDFs. At the top of that submenu, you will see the current default app, often marked with a checkmark. Click the app you want to use instead. A new window will open showing that PDF in your chosen app.

Close that window and right-click the same PDF again. Go back to "Open With" and click the app you just selected. This time, look for a button or option that says "Change All" — it appears at the bottom of the "Open With" menu. Click it, and you are done. Every PDF on your Mac will now open in that app by default.

Common PDF apps and what they do

Preview comes built into every Mac and handles basic PDF viewing, annotation, and simple editing. It opens quickly and works well for reading and marking up PDFs with highlights or notes. If you just need to view PDFs and occasionally add a comment, Preview is usually enough.

Adobe Acrobat Reader is free and handles more complex PDFs, including forms with fillable fields. It is heavier than Preview and takes longer to launch, but it supports features like digital signatures and advanced form handling. Download it from Adobe's website if you work with forms regularly.

PDF Expert and PDFtk are third-party apps you can buy or download. They offer features like merging PDFs, extracting pages, or batch processing. These are useful if you work with PDFs as part of your job, but they cost money and are not necessary for casual use.

Web browsers like Chrome, Safari, and Firefox can all open PDFs. Setting your browser as the default means PDFs open in a tab rather than a separate window. This works well if you prefer keeping everything in your browser, though browsers are generally slower at rendering complex PDFs than dedicated PDF apps.

Why your PDF might not open in the app you set

Changing the default only affects PDFs you open by double-clicking them in Finder. If you click a PDF link in an email, Safari, or a web page, that app may open the PDF in its own viewer instead of using your default. This is by design — email clients and browsers often have their own PDF handlers.

To change how PDFs open from links in Safari, go to Safari settings, find the "General" tab, and look for "PDF Viewing" or "Open PDFs in". You can set a different default there. Gmail and other web-based email do not let you change this — they always open PDFs in your browser.

If you download a PDF from the web and it opens in your browser instead of your chosen app, check your browser's download settings. Some browsers are set to open downloaded files automatically in their built-in viewer. You can usually turn this off and let the file open in your default app instead.

Changing defaults for other file types

The same "Open With" and "Change All" method works for any file type on your Mac — Word documents, images, spreadsheets, and more. You can set different defaults for different types, so PDFs might open in Preview while Word files open in Microsoft Word or Google Docs.

If you want to see all the defaults you have set across your Mac, go to System Settings (or System Preferences on older Macs), find "General", and look for "Default Apps" or "Default Web Browser". Not all file types appear there, but the most common ones do. You can change them from that screen instead of using the "Open With" method.

Troubleshooting when "Change All" does not appear

If you right-click a PDF and "Open With" shows only one app with no "Change All" button, the file may be corrupted or macOS may not recognize it as a PDF. Try right-clicking a different PDF file. If "Change All" appears for that one, the first file was the problem.

If no PDF shows a "Change All" button, restart your Mac. Sometimes the Finder needs to refresh its file type database. After restarting, try the process again with any PDF file.

If you have recently updated macOS and your default PDF app stopped working, the update may have changed your settings. Go through the "Change All" process again to reset it. This is rare but happens occasionally with major macOS updates.

Frequently Asked Questions

Can I set a different default app for PDFs on my Mac than on my iPhone?

Yes. Mac and iPhone have separate settings. Changing the default on your Mac does not affect your iPhone, and vice versa. Each device has its own "Open With" menu and default app settings.

What happens if I delete the app I set as my default PDF opener?

If you uninstall the app, macOS will revert to Preview the next time you try to open a PDF. You can then set a new default using the same "Change All" process.

Does changing the default PDF app affect PDFs I have already opened?

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

Can I set a default app for only some of my PDFs, not all of them?

No. The "Change All" button applies the default to every PDF on your Mac. If you want to open specific PDFs in a different app, right-click them and choose "Open With" without clicking "Change All".

Why does my PDF open in Safari even though I set a different default?

Safari and other browsers often override the system default for PDFs found on the web. Check your browser settings for a PDF viewer option. For Safari, go to Settings, General, and look for PDF handling options.