We recently put in a Konica 1085 with a Creo Rip. We are able to ping the Rip from all of our prepress workstations (mostly Macs). Over time, the hot folders become unaccessible by all of the workstations except 2 stations that are have OS Yosemite on them. Other workstations have slightly older OS. (The oldest at OS 10.8.5.) The only current solution is to reboot the Rip. Then the hot folders reappear and become usable. However a few hours later, gone. The Rip has a static IP address. We have never had this problem with other digital machines, including 4 other Konicas that are currently running right beside this one. Konica and Creo haven't been able to determine what is causing this. Any ideas?