Have just installed 3.12.3 for mac OS X.
I can only get it to pick up 10 USB Block Erupters. The rest give me this, SEM: Icarus USB timeout waiting for (65547) '/tmp/cgminer-usb-20-10'
Any help would be muchly appreciated.
A usb failure can show up in so many ways, this is one of them. Likely there's just not enough power.