Android 6 and the wugfresh nexus toolbox problem

Since i have updated to android 6 i have not been able to do a complete backup in the root toolbox as have have before with other android software ?The phone does not go into the adb backup mode?Any ideas why?Thanks

Wugfresh & marshmallow-red triangle/corrupt image question

Is it possible to install TWRP onto my Nexus 6 then root with supersu, then install a different kernel? I'm trying not have the stupid red triangle apart but every time I try to install and root, it says I'm corrupt?

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