If some of your tasks have disappeared from the list, please firstly make sure that you haven’t selected any filters for this specific list. If the filter is selected, it will be visible at the bottom of the screen on iOS and iPadOS, at the top of the list on watchOS, and in the toolbar underneath the list’s title on macOS. If you would like to see the completed tasks in the list as well, please tap the ‘Hidden Tasks’ button in the menu that you can access by tapping on the ‘Settings’ button in the top right corner of the tasks list on iOS and watchOS. On iPadOS and macOS, simply tap on the ‘Eye’ icon in the toolbar of the tasks list.