I think I am not the only person that encountered this frustrating problem when upgrading to CC 2018: Dolby Codec not supported on Win 7! Even if you downgraded to the latest PR 2017, the problem is not solved, because Adobe removed the support for this codec in updates after 11.0. So if you still want to use PR 2017 on Win 7, you have to install the old version 11.0. I tested it. It works. Hope this can help you.