Directly from Wikipedia :
Samsung Knox provides security features that enable business and
personal content to coexist on the same handset. The user presses an
icon that switches from Personal to Work use with no delay or reboot
wait time.1 The manufacturer has claimed this feature will be fully
compatible with Android and Google and will provide full separation of
work and personal data on mobile devices and "addresses all major
security gaps in Android.
(Download Android Terminal Emulator) then
pm disable com.sec.knox.seandroid
and after disable, maybe you need this again ;
pm enable com.sec.knox.seandroid
And i suggest you, in the
SuperSu never touch For Disabling the Knox.
it maybe harassment you and need for the second root process.(this is happend for me, but maybe you need to try it).
Also , read these articles :
How to Disable KNOX Security
HOW TO REMOVE KNOX AND PREVENT POSSIBLE ROOT ISSUES CAUSED BY KNOX
How do I Remove or Uninstall KNOX