For over 50 sessions I have recorded 22 tracks @ 24/96 with the UFX to a MacBook Pro (2011 17"). First with Pro Tools 9 and then PT 10. PT 10 was wont to crash, too often, under certain capricious conditions. So I changed my internal HD to a faster 7200 rpm drive then connected my external data HD to an eCard eSata adapter (instead of slower USB or FW)-really not much improvement.

For my last session I changed my MacBook boot/program hard drive to an internal SSD (256Gb, M4 Crucial). PT 10 seems to be stable while recording now. So it appears the problem was too slow PT 10 software swapping out operations to the ext HD which would, eventually, back up and PT 10 would crash. The Crucial is about $205 at Amazon-cheaper than the final expedient of a Thunderbolt ext SSD RAID. YMMV.

Note my post, elsewhere on this forum, of the use of the same M4 Crucial SSD (128GB-rated as only slightly slower than the 256/512 Gb) to record 22 24/96 DURec tracks for as long as 4 hours with no errors.