Hello, I routinely use my Imacon 848 with current Mac hardware (MacBook Pro, Retina, 13-inch, Late 2013, and OS X 10.11.6/El Capitan). I do find that the cabling and turn-on sequence is a bit fussy, so I use a high-quality, dedicated Firewire cable, and an Apple Thunderbolt/Firewire adapter. In case it's useful, here's how I make the connection:
* FlexColor
* launch FlexColor on MacBook Pro
* File > Devices, select Imacon 848
* Imacon 848
* power the scanner on
* Belkin Firewire cable is left permanently connected to Imacon
* cables
* with both devices running, connect Imacon and MacBookPro by plugging in the Firewire/Thunderbolt adapter to the Mac's Thunderbolt port
* Imacon will be recognized by FlexColor 4.8.13 during a Preview
* troubleshooting: if the scanner is not found for some reason, reset FlexColor > Devices to 848, and select Preview again
Good luck!
Christopher Campbell
http://cbcampbell.com