Since upgrading to Yosemite I found that my CUPS based printer was not working. Looking at the console logs it appears that this is due to an issue with sandboxing in Ysomite. I eventually found one site with a solution which fixed my problem – i.e. relax sand-boxing for CUPS so that it works again http://www.macobserver.com/tmo/forums/viewthread/86495/#652649. This works much better than any of the other methods of dealing with sand-boxing (e.g. moving the ghostscript files or editing the .ppd definition). It does however bypass the point of sand-boxing, thus introducing the risk of s security hole in the system, but until someone comes up with a version of CUPS that supports sand-boxing, relaxing the requirement seems the easiest solution.