How to Change Default PDF Viewer on Mac: The Complete 2026 Guide

Before we dive into the methods, it is important to understand how macOS handles file associations. Unlike Windows, which often prompts you to choose a default app when you install a new one, macOS is protective of its defaults.

When you double-click a file, the system checks Launch Services—a core component of the operating system that maintains a database of which applications claim support for which file types. By default, Apple hardcodes Preview as the priority handler for the .pdf extension (Portable Document Format).

Changing this association requires a deliberate action from the user. Simply installing Adobe Acrobat Reader or Foxit PhantomPDF is not enough to take over the association. You must explicitly tell Launch Services to update its registry.

This is the "Gold Standard" method. It is the official way Apple intends for you to manage file associations. It is permanent, reliable, and affects every single PDF file on your system, present and future.

Step-by-Step Instructions

1. Locate a Target File: Open Finder (the smiling face icon in your dock) and navigate to any PDF file on your computer. It does not matter which one; the change will apply globally.
2. Open Information Panel: Right-click (or Control-click) on the file. In the context menu that appears, select Get Info. Alternatively, you can highlight the file and press the keyboard shortcut Command ⌘ + I.
3. Access 'Open with' Settings: A long, narrow window will pop up containing file details. Look for a section titled Open with:. If the details below it are hidden, click the small grey arrow (chevron) next to the text to expand the section.
4. Select Your New App: You will see a dropdown menu that likely says "Preview.app (default)". Click this menu to see a list of installed applications that can handle PDFs. Select your desired viewer (e.g., Adobe Acrobat Reader, Google Chrome, PDF Expert).
5. The Critical Step: After selecting the new app, you will notice a button below the dropdown labeled Change All... become active. You must click this button. If you do not, the change you just made will only apply to that single file you clicked on.
6. Confirm System Prompt: A dialogue box will appear asking: "Are you sure you want to change all similar documents to open with the application 'Adobe Acrobat'?". Click Continue.

Sometimes, you don't want to change the global default. Perhaps you want to use Preview for quick reading but need Adobe Acrobat for signing a specific contract.

In this case, use the context menu override:

1. Right-click (Control-click) the specific PDF.
2. Hover over Open With > in the menu.
3. Select the specific app you want to use for this session.

Pro Tip: If you hold down the Option (Alt) key while in the "Open With" menu, the option changes to "Always Open With". This performs a similar function to Method 1 but only for that specific file!

Not all PDF viewers are created equal. Choosing the right default depends heavily on your daily tasks. Here is a detailed breakdown of the major contenders on macOS.

Did you follow Method 1 but your Mac is "fighting back"? Here are advanced solutions for stubborn systems.

Issue 1: The Setting Reverts After Restart

If macOS keeps switching back to Preview after a reboot, your Launch Services database might be corrupted. You can rebuild it using the Terminal.

Paste the above command into Terminal and press Enter. Wait for the process to finish, then restart your Mac and try Method 1 again.

Issue 2: "File Info" is Locked

Look at the bottom right corner of the "Get Info" window. Is there a small lock icon? If it is closed, you don't have permission to change settings for this file. Click the lock, enter your administrator password, and try again.

Issue 3: Adobe Acrobat Keeps Asking to be Default

Many PDF apps have an internal check:
Acrobat: Preferences > General > Select Default PDF Handler > Select Adobe Acrobat DC.
Using the in-app button often forces a system prompt that simplifies the process.

Even with a powerful default viewer like Acrobat, you might find yourself needing to perform quick edits without waiting for heavy software to load. This is where cloud-based (or local-browser) tools act as the perfect companion workflow.