Tommy197944 - i have tried all 4 USB ports as well as different USB cables. I took the drive to the Apple Store where they tried it on several different systems. iMAC running OS X 10.8.5; MACbook Pro running OS X Lion and a MACbook Pro running OS X 10.8.5. Both MACbook Pros mounted the drive but the iMAC failed to mount the drive. I remember a blog response saying swapping the OS X Mountain Lion's DVDPlayback.Framework file for OS X Lion's DVDPlayback.Framework might solve the issue.
It is perplexing that the exact same Samsung DVD Writer, model SE-208DC/TSWS mounts on MACbook Pro running the latest version of Mountain Lion (10.8.5). That MACbook Pro also had an internal DVD Writer. The Samsung DVD Writer was also tested on a MACbook Pro running Lion and it also mounted correctly. So what did Apple change in OS X Mountain Lion that would prevent the iMAC from mounting the external Samsung DVD Writer. The Samsung DVD Writer has no drivers for the MAC. It depends on the OS X files. I am trying to keep a positive attitude and hoping Apple did not change OS X Mountain Lion to prevent 3rd party external DVD Writers from mounting correctly with the new IMACs that no longer can be configured with an internal DVD Writer.
Most grateful for some proven solutions.