Missing Previews

[Manti]

 I just upgraded to version 5.1.2 and when I opened my first sequence, when it prompts for the upgrade for the sequence it offers either my 2016 previews or to create one from the 2017 sequence.  It doesn't show my 2017 previews as options even though the 2017 visualizations are in the visionization/editor folder with the 2016 files.  I'm sure I'm doing something wrong but I have looked here and in the Help and haven't identified what it might be.

Any suggestions would be appreciated.