In reply to Andrew Konstantaras.

The only thing that comes to my mind is to make sure you have disabled SIP (you have to reboot into recovery mode, launch the terminal from Utilities/Terminal, run csrutil disable and reboot).

Allowing unsigned kexts (which on El Cap requires disabling SIP aka rootless) is necessary for SoundBlossomer to work properly: it changes the Info.plist file inside the kext, thus making its signature not match and causing OS X to run around screaming. Unfortunately AFAIK there's no way to whitelist a single unsigned kext.