What default apps and file associations do
A default app is the program your device automatically opens when you click on a file. A file association is the link between a file type and the app that opens it. When you double-click a PDF, your computer looks up what app is associated with PDFs and launches that one. If you have three PDF readers installed, the default app is whichever one you set to open PDFs by default.
You control these associations. If you want PDFs to open in Adobe Reader instead of your web browser, or Word documents to open in Google Docs instead of Microsoft Word, you can change the default. You can also set different defaults for different file types — your photos might open in one viewer, your videos in another.
Default apps matter because they affect your workflow. Opening a file in the wrong program wastes time. Some programs also set themselves as defaults during installation without asking, which can surprise you the first time you click a file and it opens somewhere unexpected.
Key Takeaways
- Default apps are set per file type, so you can have PDFs open in one program and Word documents in another.
- On Windows, you change defaults in Settings under Apps, and on Mac, you right-click a file and choose "Open With" then "Always Open With".
- Some programs automatically set themselves as defaults during installation, so check your defaults after installing new software.
- You can set a program as the default for a single file type without changing defaults for all file types that program handles.
How to change defaults on Windows
Open the Settings app by pressing the Windows key and typing "Settings", then press Enter. Click Apps in the left sidebar, then click Default apps. You will see a list of file types and the program currently set to open each one.
To change a single file type, click on the program name next to that file type. A menu will appear showing other programs installed on your computer that can open that file type. Click the program you want to use instead. The change takes effect when ready.
If you want to set one program as the default for multiple file types at once, scroll down to find that program's name in the list and click it. You will see all the file types it can handle, with toggles next to each one. Turn on the toggles for the file types you want this program to handle by default.
How to change defaults on Mac
Right-click (or Control-click) any file of the type you want to change. A menu will appear. Click Open With, then look for the program you want to use. If you see it in the list, click it once to open just this file, or hold down Option and click it to open this file and set it as the default for this file type going forward.
If the program you want is not in the "Open With" menu, click Other at the bottom of the menu. A file browser will open. Navigate to your Applications folder, find the program, click it, then click Open. A dialog will ask whether you want to open just this file or change the default for all files of this type. Choose accordingly.
Alternatively, open the program itself and look in its preferences or settings menu. Many Mac programs have an option to set themselves as the default for certain file types. This is often faster than the right-click method if you are setting multiple file types at once.
What to do if a program keeps resetting your defaults
Some programs automatically reset themselves as the default when they launch, undoing your choices. This is frustrating and common with web browsers and media players. The program is designed to do this, and there is no universal way to stop it — each program handles it differently.
Check the program's settings or preferences menu first. Look for an option like "Check if this is the default browser" or "Set as default on startup" and turn it off. If you find that option and disable it, the program should stop resetting your defaults.
If the settings menu does not have that option, you may need to accept that this program will reset your defaults when it runs. In that case, set your defaults only when you are about to use a file and do not plan to launch the problematic program afterward. Alternatively, uninstall the program if you do not use it regularly enough to justify the inconvenience.
File types and which programs handle them
Common file types and their typical defaults are listed below. Your computer may have different programs installed, so your options will vary.
| File Type | Common Default Programs | What It Is |
|---|---|---|
| Adobe Reader, web browser, Preview (Mac) | Documents formatted for printing and sharing | |
| DOCX, DOC | Microsoft Word, Google Docs, LibreOffice | Word processing documents |
| XLSX, XLS | Microsoft Excel, Google Sheets, LibreOffice | Spreadsheets |
| JPG, PNG, GIF | Photos app, Preview (Mac), Windows Photos | Image files |
| MP4, MOV, AVI | Windows Media Player, VLC, QuickTime (Mac) | Video files |
| MP3, WAV, FLAC | Windows Media Player, iTunes, VLC | Audio files |
| HTML | Web browser (Chrome, Firefox, Safari, Edge) | Web pages |
| ZIP | Built-in file manager (Windows and Mac) | Compressed folders |
Why programs change your defaults during installation
When you install a new program, it often sets itself as the default for file types it can handle. This happens because the program's installer includes a step that changes your defaults without asking clearly. Some installers have a checkbox you can uncheck to prevent this, but you have to look for it — it is often buried in the "Advanced" or "Custom" installation options.
To avoid unwanted default changes, always choose Custom or Advanced installation instead of clicking through with the default "Quick" or "Express" option. Read each screen carefully and uncheck any boxes that say the program will become your default for certain file types. After installation, check your defaults to confirm nothing changed unexpectedly.
Frequently Asked Questions
Can I have different default apps on different user accounts on the same computer?
Yes. Each user account on your computer has its own default app settings. If you share a computer with someone else, you can each set your own defaults without affecting the other person's. Changes you make in Settings or through right-click menus explore only to your account.
What happens if I delete a program that was set as a default?
If you uninstall a program that was set as the default for a file type, your computer will usually ask you to choose a new default the next time you try to open that file type. If it does not ask, go to your default apps settings and manually choose a different program.
Can I set a web browser as the default for opening all files?
No. Web browsers can only open file types they understand — mainly HTML, PDF, images, and video. You cannot set a browser as the default for Word documents or spreadsheets. You need different defaults for different file types.
Why does my file open in the wrong program even though I set a default?
The most common reason is that the program you set as default has reset itself since you made the change. Check your defaults again to see what is currently set. If a program keeps resetting your defaults, look in its settings menu for an option to stop it from doing so.
Do I need to restart my computer after changing a default app?
No. Default app changes take effect when ready on both Windows and Mac. You can change a default and then open a file of that type right away, and it will open in the new program.