I upgraded to 10.11 and was not able to run my boot camp vm. The fix is to disable SIP a.k.a System Integrity Protection a.k.a Rootless a.k.a Worthless. I tried cmd + R on boot and disabling through Security Configuration as stated at WWDC but recieved Mach error -536870212. A quick search on the apple dev site produced a working fix.
Open Terminal.
sudo su
[enter password]
nvram boot-args="rootless=0"
reboot
I had to reset my shared folders but other than that all seems ok... other than the USB driver error.
this was done on a late 2013 rMBP fusion 7.1.1