Windows 10 - Changing Default Apps Look for the section marked "Type here to search" at the bottom left of your screen. If your UI is condensed, this may just be a Spy Glass Click Default Apps You will have several options on how to proceed: Select an app from the list for common system functions. e.g. E-mail / Web Browser Choose default applications by file type (This is a more advanced option and is usually not necessary. Use this when you know the extension you want to change) Choose Application by protocol (as above, usually not necessary) Set Defaults by app (use this when you know what application you want to use) If the Default app you want to change is a web browser or e-mail client, click the application from the list, and change it to the app you wish to use. Otherwise (e.g. for PDFs), click "Set Defaults By App" Find and select the app for which you wish to change the active file associations (e.g. Adobe Acrobat DC) Select "Manage" Click on any entry to change this to the selected application: Close all windows when done.