1. Go to the app list and choose Settings. 2. Swipe to the left of the screen to access the applications section, and then choose background tasks from the list. 3. The background tasks section shows you all the blockable apps. By default, you should see that all apps are allowed to run in the background. Please note that not all of the background tasks are blockable. The unblockable ones are usually system apps or apps from the phone’s maker. 4. To block an app, choose the app and then tap the block button.