How to Make Preview the Default App on Mac for PDFs and Images

Mac's built-in Preview app is one of the most underrated tools in macOS. It opens PDFs, images, screenshots, and a wide range of document types quickly and without the overhead of heavier third-party apps. But depending on how your Mac is configured — or what software you've installed — Preview may not always be the app that opens when you double-click a file. Here's exactly how to set Preview as your default, where things can get complicated, and why the right approach depends on your specific setup.

Why Mac Sometimes Opens Files in a Different App

macOS assigns a default application to each file type based on file extension — .pdf, .jpg, .png, .tiff, and so on. When you install software like Adobe Acrobat, Adobe Photoshop, or Microsoft Office, those apps often reassign themselves as the default for common file types during installation. This happens silently in the background.

The result: you double-click a PDF and Acrobat opens. You open a JPEG and Photoshop launches. If your preference is Preview — especially for quick viewing rather than editing — you'll need to manually reassign those file associations.

How to Set Preview as the Default App for a Specific File Type

The most reliable method works directly from Finder and applies to all files of the same type at once:

1. Find a file of the type you want to change (e.g., a .pdf or .jpg)
2. Right-click (or Control-click) the file and select Get Info — or press ⌘ + I
3. In the Info panel, locate the "Open with:" section
4. Click the dropdown menu and select Preview
5. Click "Change All…" directly below the dropdown
6. Confirm when macOS asks if you want to change all similar documents

This sets Preview as the default for every file with that extension going forward. You'll need to repeat this for each file type you want Preview to handle — .pdf, .jpg, .png, .heic, .tiff, .gif, and others are separate assignments.

Setting Preview as Default for Multiple File Types at Once

macOS doesn't offer a single toggle that says "make Preview the default for everything it supports." You handle this per file type, which can feel tedious if you've had another app take over several formats.

A practical approach: identify which file types you open most frequently, then work through them one at a time using the Get Info method above. Common types to reassign include:

The "Change All" button in Get Info is the key step — without it, you're only changing that one file, not the file type globally.

What Happens When You Open Files From a Browser 🖥️

Browsers like Chrome, Firefox, and Safari handle PDFs somewhat independently. Even if Preview is your system default for .pdf, your browser may still open PDFs in its own built-in viewer. These are separate settings from your system file associations.

In Safari, go to Settings (or Preferences on older macOS) and look at how downloads are handled. In Chrome, you can adjust PDF behavior under Settings > Privacy and security > Site settings > Additional content settings > PDF documents. Toggling "Download PDFs" rather than opening them in-browser means they'll land in your Downloads folder and open with your system default — which would be Preview if you've set it that way.

After a macOS or App Update

One detail worth knowing: major macOS updates and reinstallations of third-party apps can reset file associations. If you've installed a new version of Adobe Acrobat or updated your system and Preview is no longer opening your files, the file type reassignment likely got overwritten. The fix is the same — Get Info, change the default, apply to all — but it may need to be repeated occasionally depending on your software ecosystem.

When Preview Isn't the Best Fit for Every File 📄

Preview handles a broad range of formats well for viewing, light annotation, and basic PDF editing tasks like merging, reordering pages, filling forms, and adding signatures. It's genuinely capable for everyday use.

That said, some workflows push against its limits. If you regularly work with layered image files, complex PDF forms, professional color profiles, or high-volume document editing, you may find that a more specialized app handles certain file types better for your specific work. The question of whether Preview is the right default for every file type on your machine depends heavily on what you're actually doing with those files day to day.

The Variable That Changes Everything

The mechanics of setting Preview as your Mac default are straightforward and consistent across recent macOS versions. The more nuanced question is which file types to reassign and whether Preview should be the default for all of them or just some.

That depends on your installed apps, your typical workflows, and whether you're optimizing for quick viewing or active editing. A user who only reads PDFs casually has very different needs from someone who annotates, fills forms professionally, or edits images regularly. Your installed software, the macOS version you're running, and how those apps behave after updates all shape what "setting Preview as default" looks like in practice — and how long it stays that way.