Hi I am not able to use my Samsung Galaxy S4 I9500 I had bought 6 months back. I am getting 3 errors: 1) an application has been forced to stop for an unauthorized attempt to access system in your device. 2) Network will be unavailable until you insert a valid sim card 3) No SIM When I click the notification of error it takes me to Samsung Knox Notification Manager. As I understood for many trials & errors, The problem is Knox I have tried following to resolve the issue. 1) Factory Reset 2) Went to Samsung Authorized Service Centre, They Flashed it but it didn't work 3) inserted multiple Sim cads 4) Installed 'Root Explorer' & deleted all knox files: It says 'Delete Failed' 5) Used 'Terminal Emulator' & did this: su pm disable com.sec.knox.seandroid It said couldn't find 'su' 6) Tried using 'Titanium Backup' : it said ' you don't have root access Please some one help me, as i'm not able to use my phone since last 3 weeks.