Samsung's devices of late have been tricky to root not because they are with a restricted bootloader, or anything of the sorts, but rather because of KNOX - Samsung's enterprise-grade security software that comes preinstalled. So far, there hasn't been a reliable way to root the S6 without tripping this software's counter, and flagging it as such means that your warranty will be void. Samsung's after-sales service will read "KNOX WARRANTY VOID: 0×1", and refuse to bother with your perceived drama.
Thankfully, when there is a will, there is a way, and this either/or situation is finally coming to an end thanks to the new PingPong root tool by developer idler1984. It allows you to gain Superuser access without getting the official KNOX counter all hot and bothered about it. Here's what you need to do to get one-click root with PingPong, keeping KNOX intact:
1. Download the party_beta5.7z package on your phone, or sideload the archived app;
2. Unpack it, allow apps from unknown sources in your settings, and run the PingPong root installer;
3. Open PingPong, and just tap on the "Get root" button - if it asks for any permissions, allow those. Run it another time, if it doesn't root from the first time;
4. Reboot when recommended, then go and search for the new Kinguser app that PingPong would have installed;
5. Open Kinguser, and tap on the "Root authorization" section, then grant access to the Root Checker app by tapping on the "Prompt" arrow on the right of the Root Checker app listing, and choosing the green "Allow" checkmark;
6. Run the Root Checker app, and pat yourself on the back if it says "Congratulations!"
That's all, folks, you now should have root access to your precious little Galaxy S6 and S6 edge phones without having tripped the KNOX counter, confirmed working on the Verizon version, too - can't get much easier that that. Alternatively, there is a nice and sweet video tutorial you can follow.
source: idler1984 (XDA-Devs)