I am one of the people affected by the El Capitan not booting issue. It seems to be connected to unsigned kexts.
So I did a clean install and after everything was fine until software for my printer got installed. I use a HP Photosmart Plus AIO B210. After the automatic installation of printers, my Mac fails to boot.
After having deleted hp_io_enabler_compound.kext my Mac booted again, but now I can't use my printer, which *****. What should I do?
MacBook Pro (Retina, Mid 2012), OS X El Capitan (10.11.1)