This is the USB2Lan adapter causing Kernel Panic with Calibre on Mac OS X 10.11.6 :
http://www.aliexpress.com/item/U3-09...8.0.115.LsNhAm
On Windows 10, there is no crash, even if this adapter is connected (seen as "Realtek USB GbE Family Controller" with ID "USB\VID_0BDA&PID_8153&REV_3000").
Regards