Hello! I just bought a Panasonic UJ-267 for my Late 2009 Mac mini running OS X 10.11.6 and it's having a strange issue. Every so often it thinks there is a disc inserted (even though their isn't) and it won't let me insert a new one. When this happens, I need to go to terminal and run "drutil tray eject". The drive makes the ejecting noise, nothing comes out, and I'm now able to insert a disc. Anyone have any idea why this is happening? Defective drive? It's brand new... could be a dud? Bought it from OWC and they are willing to exchange, but I want to eliminate anything else as the cause before I rip apart my mini again. Thanks!