On the bottom right corner select settings Next, select "app manager", this will bring up a list of all your applications. There will be three tabs: Downloaded, All and Runing. Please select "All" tab. On the upper right hand corner, tap on "Select by Size". The application should be on the top of the list.Tap on "Textbooks". Tap on "Clear Data". Go to?Apps?screen and open our app, Textbooks.These instructions were given by kno customers services and it work for me. Share on any forum with the same problem