Switched in October 2016. Yes, I am using a custom workspace. I will try your suggestion. I just re-installed VW on a new iMac with Sierra OS. I did realize after I posted that it appears to be a problem with groups created in a previous version of VW (mostly VW 2012 drawings converted forward), when I extracted all of the elements within the group at it's lowest level and then pasted in place, and grouped.....well, then the ungroup command works.
Thanks for the suggestions.