How to change which app opens a file type by default on a Mac
Double-click a PDF and it opens in an app you didn't choose. Install a new photo editor and suddenly every JPEG opens there instead of Preview. macOS decides which app handles each file type, and it lets you override that decision from a file's Get Info window. This guide changes the default for every file of one type. The Variations section covers changing it for a single file, and the separate settings for your web browser and email app.
What you'll need: One file of the type you want to change, and the app you want to open it with already installed on the Mac.
Find a file of the type you want to change
Open a Finder window and find any file with the right extension — a .pdf if you want to change how PDFs open, a .jpg for photos, a .txt for plain text, and so on. Which file you pick doesn't matter. The change will apply to every file that shares its extension.
Open the Get Info window
Click the file once to select it, then press Command + I. A window opens showing the file's details.
You can also right-click the file (or hold Control and click it) and choose Get Info from the menu.
Find the "Open with" section
Scroll down the Info window until you see a heading labelled Open with:. Under it is a drop-down menu showing the app that currently opens this file.
Choose the app you want
Click the drop-down menu and pick the app from the list. macOS lists the apps it knows can open this type of file, with the current default at the top.
If the app you want isn't listed, choose Other… at the bottom of the menu. A window opens showing your Applications folder. Click the app you want, then click Add.
Click Change All…
Directly below the drop-down menu is a button labelled Change All…. Click it.
Without this step, the change only applies to the one file you selected. Change All is what makes it the default for every file of that type.
Confirm the change
A message asks whether you're sure you want to change all similar documents to open with the app you picked. Click Continue.
There is no Save button. The change takes effect straight away, and you can close the Info window.
Test it on a different file
Find another file with the same extension and double-click it. It should open in the app you chose. If it opens somewhere else, see Troubleshooting below.
Variations
Follow steps 1 to 4, then close the Info window without clicking Change All…. That one file will now open in the app you picked every time, and every other file of the same type carries on opening as before. This is useful for a single spreadsheet you always want in Numbers while the rest stay in Excel, say.
Right-click the file and hover over Open With. A list of suitable apps appears. Click the one you want. The file opens there this time only, and the default is untouched.
These aren't tied to a file type, so Get Info won't help. For the browser, open System Settings, click Desktop & Dock, and scroll down to Default web browser. For email, open Apple's Mail app, choose Mail › Settings from the menu bar, and change Default email reader on the General tab. Yes, this is set inside Mail even if you never use Mail.
Troubleshooting
macOS only highlights apps it thinks can open that file type. At the bottom of the window there is a drop-down labelled Enable, set to Recommended Applications. Change it to All Applications and the greyed-out app becomes clickable. If the app can't actually read the file, it will tell you so when you open one.
This happens when the app shown in the menu is already the default for that file type, so there is nothing to change. Check that you picked a different app in step 4. It can also happen if the file has no extension at all, because macOS has no "type" to apply the change to.
Those files probably have a different extension than you think. A photo might be .heic rather than .jpg, or a document .docx rather than .doc, and each extension has its own default. To see extensions, open Finder › Settings from the menu bar, click Advanced, and tick Show all filename extensions. Then repeat the steps for each extension that needs changing.
Some apps make themselves the default for their file types when you install or first open them. Repeat the steps above and the setting will stick until the next app does the same.
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