App data is the data that is accumulated and stored (often unnecessarily) on your device when you use certain apps. CCleaner Android identifies app data that you should be able to safely remove from your device. When using this feature, consider the impact that removing app data may have on the functionality of the source app. For example, each time you open Google Maps, the app re-downloads any offline maps that were removed by CCleaner Android. Similarly, Spotify re-downloads offline tracks when needed. Conversely, deleting OBB type app data, which is often associated with large games, may release a lot of space on your device while allowing you to keep the game, but, you may need to reinstall or re-download the OBB file if you decide to continue the game.