How to Change the Default App for a File Type on Mac

Double-click a photo and it opens in an app you never use. Click a PDF and it launches a slow program instead of the quick one you prefer. Every file type on your Mac has a default app assigned to open it, and those assignments are easy to change — for one file, or for every file of that type at once. The trick is knowing the difference between the two methods, because picking the wrong one only fixes a single file. This guide shows both, plus how to handle stubborn cases where an app keeps stealing your file types back.

Quick Answer

To change the default app for a file type on a Mac, select any file of that type in Finder, press Command-I to open Get Info, choose your preferred app in the “Open with” section, then click “Change All” and confirm. From then on, every file with that extension opens in the new app. To change the app for just one file, use the same window but skip “Change All,” or right-click the file, hold Option, and choose “Always Open With.”

Change the Default for Every File of That Type

1. In Finder, find any file with the extension you want to change — for example, any .pdf file.
2. Click the file once to select it, then press Command-I, or right-click it and choose Get Info.
3. In the Get Info window, look for the “Open with” section. If it is collapsed, click the small triangle to expand it.
4. Click the dropdown menu showing the current app and choose the app you prefer. If your app is not listed, choose “Other” and pick it from the Applications folder.
5. Click the “Change All” button directly beneath the dropdown.
6. A confirmation asks if you are sure you want all documents like this one to open with the app. Click Continue.
7. Close the Get Info window and test by double-clicking another file with the same extension.

That is the whole job. The change applies to every file with that extension across your Mac — images (.jpg, .png), documents (.docx, .txt), archives (.zip), videos (.mp4, .mov), and anything else. Repeat the process per extension; changing .jpg does not change .png, because macOS treats each extension as its own type. Apple’s support article on choosing an app to open a file covers the same menus with screenshots for each macOS version.

Change the App for One File Only

Sometimes you want one specific file to open elsewhere — a single photo in an editor while the rest stay in Preview, for example. Right-click the file, choose “Open With,” and pick the app for this one time. To make that one file always use the other app while leaving its siblings alone, right-click it, hold down the Option key so “Open With” becomes “Always Open With,” and select the app. Or open Get Info for that file, set “Open with,” and simply do not click “Change All.” macOS remembers the individual assignment for that file from then on.

Common Assignments Worth Changing

• PDFs: Preview is fast and free and even signs documents; many people switch away from heavier readers they installed once and forgot.
• Images: Keep Preview for quick viewing, or set your photo editor as default if you edit almost every image you open.
• Video files: QuickTime handles common formats, but a dedicated player opens far more types, including .mkv files QuickTime refuses.
• Archives: The built-in Archive Utility handles .zip well; other formats like .rar need a specialist app set as default to stop error messages.
• Text and code files: Plain .txt files open in TextEdit by default; a proper text editor is a better home if you edit notes or code daily.
• Music files: Set individual albums to open in a specific player without changing the default for your whole library, using the one-file method.

Defaults pair naturally with how you organise your Mac overall — the same “set it once, benefit daily” idea behind using Finder tabs and tags to organise your files.

When the Default Keeps Reverting

If a file type keeps snapping back to an app you dislike, something is re-registering it. The usual causes: the rival app updates itself and reclaims its file types (check that app’s preferences for an option like “set as default” and turn it off), or you are clicking “Change All” in a Get Info window for a file stored on a read-only or network volume, where the change cannot save properly — copy the file to your Desktop, change it there, and the setting sticks. Also make sure your chosen app is actually installed in the Applications folder; an app running from a disk image or Downloads cannot hold a reliable default assignment. If everything fails, signing out and back in refreshes the Launch Services database that tracks these assignments.

How to Reset a File Type Back to Apple’s Default

There is no single “reset all” button, but reversing a change is the same process: pick any file of the type, open Get Info, choose the original Apple app (Preview for images and PDFs, QuickTime Player for videos, Music for audio, TextEdit for plain text), and click Change All. If you cannot remember the original, the dropdown’s recommended apps at the top of the “Other” picker are the system’s own — selecting one of those restores the factory feel.

Common Mistakes to Avoid

• Skipping “Change All.” Without it you only changed one file. This is the single most common reason people think the feature “doesn’t work.”
• Expecting one change to cover similar extensions. .jpg and .jpeg and .png are separate types; change each one you care about.
• Choosing an app that is not installed properly. Apps run from disk images or the Downloads folder cannot hold defaults reliably. Install them into Applications first.
• Confusing “Open With” for one file with the system default. The right-click menu alone is a one-time choice unless you hold Option for “Always Open With” or use Get Info’s Change All.

Defaults for Files With No Extension and Other Edge Cases

Some files — common on Macs that exchange documents with older systems or download archives — arrive with no extension at all, and macOS then guesses from the file’s contents, sometimes badly. For those, the right-click “Open With” menu is your tool each time, or you can rename the file to add the correct extension (.txt, .jpg, .pdf) and the normal default rules take over; just be sure you know the true format before renaming. Another edge case is files stored inside apps, such as photos in the Photos library: those open inside their app by design, and defaults only apply when you export or drag the file out to Finder. None of this is a fault — it is simply where the boundary of the default-app system lies, and knowing the boundary saves you hunting for a setting that does not exist.

Conclusion

Your files should open in the apps you actually like. Get Info plus “Change All” sets a new default for an entire file type in under a minute, the Option-key trick handles single files, and defaults can always be reversed the same way. Set the handful of types you touch every day — PDFs, images, videos, archives — and your Mac quietly feels more like yours.

Frequently Asked Questions

Why is the “Change All” button greyed out?

Usually because the file sits on a read-only volume or a network share, or you lack permission to change it. Copy the file to your own Desktop and try again.

Can I set different default apps for two files with the same extension?

Yes — per-file assignments override the type default. Use “Always Open With” on a specific file and it keeps its own app while others follow the general rule.

Does changing the default app affect files I already sent to other people?

No. The setting only controls what happens on your Mac. The files themselves are unchanged and open normally on anyone else’s computer.

How do I change which browser opens links?

That is a separate setting: open System Settings, go to Desktop & Dock, and choose your default web browser there. Email links follow the default email reader setting in the Mail app’s settings.

Will uninstalling an app break my file defaults?

macOS automatically falls back to another suitable app for those file types. You may want to set a fresh default with Get Info afterwards so the fallback is the app you actually want.