This only started happening since I began using PP2017 on my 2012 iMac running Yosemite 10.10.5. I've never installed any audio plug-ins and I'm certainly not using Premier Pro version 1.0. As stated in my original post, it doesn't prevent me from completing the process, but the message just doesn't make sense to me. Is no one else seeing this since updating to PP2017? Maybe the next bug fix will take care of it.