You have hundreds of different types of files on your PC, and probably multiple programs that can open each one. Windows makes it easy for you to open up these files by setting up default programs for each file type -- images files, for example, will open by default in the Windows 10 Photos app.
But what if you're not a fan of Windows 10's default programs, or you install a program that automatically sets itself to be a default program (and you want to switch it back)? You'll need to go into the Settings menu to change the default programs and apps for different file types and protocols.
1. To change the default programs for files and protocols, you'll need to open the Settings menu and go to System > Default apps.
2. Here, you can change the programs you want to use for your calendar, email, maps, music player, photo viewer, video player, and Web browser. Just click the current default app to see a pop-up menu with other possible apps you can use, or a link to the Windows Store.
3. To set defaults for individual file types (e.g., instead of using one program to open all photo files, you want to use different programs to open JPEGs and PNGs), click Choose default apps by file type. Find the file type you want to change the default app for, click the current default app, and choose the app you want to use from the pop-up menu.
4. To set defaults for individual protocols (e.g., you want to set up your PC so that Gmail opens when you click an email address on a Web page), click Choose default apps by protocol. Find the protocol you want to change the default app for, click the current default app, and choose the app you want to use from the pop-up menu.
5. Changing default programs for individual file types and protocols can be tedious. Instead, you can set defaults by program/app by clicking Set defaults by app. This will open the Set Default Programs Control Panel window. Choose a program and click Set this program as default to set the program as the default program for all file types and protocols it's capable of opening, or click Choose defaults for this program to pick individual file types and protocols from a list.