I'm having a problem with an Epson Expression 1680 scanner and OS X 10.11.3. The scanner is connected to my Mac (mid 2010 Mac Pro) via FireWire. The FireWire port on the scanner is FW 400. I use a FW400 --> FW800 adapter on the cable to plug it into my Mac. The scanner is not recognized by the Mac (I have been using Preview as the scanning interface). This system has worked fine for years, including up to and including OS X 10.9 (I believe I went from 10.9 to 10.11; don't remember if I did 10.10). I don't scan often, so I am not sure when this problem first appeared. Interestingly, I have an external drive with 10.6.8, so I booted into that. Scanner was recognized as normal, and I was able to complete my scanning project. Rebooted back into 10.11.3 and again, scanner was not recognized. So there does not appear to be an obvious hardware problem with either the scanner, the cable or the FW400-->FW800 adapter. The external disk with OS X 10.6.8 is attached to the Mac directly via an FW800 cable (FW800 ports on both ends), and this drive was recognized without issue. I've seen other reports of FireWire issues on El Capitan, but I haven't seen an exact match to this one, nor have I seen a solution (but I haven't read everything yet). Anyone have any comments or suggestions?