How to change which app opens PDFs and other file types
When a PDF or photo keeps opening in a program you did not want, the fix takes about a minute. Here is how to pick the right app on Windows and on a Mac.
You double-click a PDF and it opens in your web browser. You double-click a photo and a program you never use jumps up. It is annoying, but it is easy to fix. Your computer keeps a list of which app opens which kind of file, and you can change that list whenever you like.
This guide shows you how to change the default app to open files on Windows and on a Mac. We do it by hand first. Then we show how to ask Key to do it for you.
First, what is a file type?
Every file ends with a short tag after the dot in its name. A report might be report.pdf, a holiday picture beach.jpg, a letter letter.docx. That tag is the file type, or extension. Your computer picks the app by looking at it.
So when you change the app for one PDF, you are really changing it for every file that ends in .pdf. That is usually what you want.
You do not need to see the tag to follow these steps. If you cannot see it on your computer, the steps below still work. You only need to know the type you are after, such as .pdf or .jpg.
Change the default app on Windows
These steps are from Microsoft's own help and work on Windows 10 and 11. The exact words on screen can differ a little between the two.
- Press the Windows key and I together to open Settings.
- Go to Settings › Apps › Default apps.
- In the search box near the top, type the file type, for example
.pdf. - Select the file type when it appears in the results.
- Choose the app you want from the list that opens.
That is all. The next time you open a file of that type, it goes to the app you chose.
Another way on Windows: start from the app
If you would rather think about the app than the file, there is a second route on the same Default apps page. Select an app in the list. Windows then shows you which file types and link types that app can open. If one is wrong, select it and choose a different app.
This is handy when one program has taken over lots of things. A photo viewer that also grabbed your PDFs, say.
If the app you want is not in the list
Only apps that are installed show up, and only apps that can open that kind of file. If your favorite PDF reader is missing, check that it is installed. If it is not, install it first, then go through the steps again.
Change the default app on a Mac
On a Mac you start from a file, not from Settings. These steps are from Apple's own help.
- Click the Finder icon in the Dock to open a Finder window.
- Click a file of the type you want to change, such as any PDF. Just click it once. Do not open it.
- In the menu bar, choose File › Get Info. You can also hold Control, click the file, and choose Get Info.
- In the Info window, click the small triangle next to Open with.
- Click the pop-up menu and choose the app you want.
- Click Change All if you want every file of this type to open in that app.
The last step matters. If you skip Change All, only that one file changes. Every other PDF keeps opening in the old app. If your Mac asks you to confirm, say yes.
This works for photos, music, text files and most other things, too. Pick a photo and you can set the app for all your pictures of that type. Pick a movie and you can do the same for videos.
Common questions
Why does my PDF open in the browser?
Browsers can show PDFs, and some computers are set to use the browser by default. Pick a PDF reader as the default and the browser will stop doing it.
I changed it, but only one file changed.
On a Mac, you probably missed Change All. Go back to Get Info and click it. On Windows, make sure you searched for the file type, such as .pdf, and not for one particular file.
Can I change my mind later?
Yes. Nothing about this is permanent. Go through the same steps and pick a different app.
What if I only want to open one file in a different app?
Right-click it (on a Mac, Control-click) and look for the Open with option. That opens just that file in the app you choose, and your default stays as it was.
Ask Key to do it
If you would rather not go hunting through menus, you can just say what you want. Key is a free assistant for Windows and Mac. You can speak to it or type to it, and both give the same result. It opens the real Settings window, or the real Finder, and presses the real buttons, then tells you what it did.
Half a sentence is enough. Key works out what you meant, does it in the real app, and checks the result before it tells you. While it works, a small panel shows what it is doing, and you can stop it at any point. It also reads the result back, and if it could not check something, it says so.
KeyVoiceOpen my PDFs in Adobe Reader instead of the browser
Done: PDF files will now open in your PDF reader instead of the browser.
This is the same kind of job as the ones in our guide to changing brightness, dark mode and other settings by voice. If you are not sure where a file lives, our guide to finding a file by what is inside it can help you track one down first, so you have something to click on.
If you are curious how Key behaves around your computer, read is it safe to let an AI assistant use your computer?
A quick checklist
- Know the file type you want to change, such as
.pdfor.jpg. - On Windows, use Settings › Apps › Default apps and search for the type.
- On a Mac, use File › Get Info › Open with and then click Change All.
- Open a file of that type to see that it works.
Once it is set, you should not have to think about it again.
Try Key free
Speak to it or type to it. It opens your apps, finds your files and changes your settings, then tells you what it did.
Free, no card. Windows 10 or 11, macOS 11 or newer.