SamBrownJBA

We are using Vectorworks 2016 (Architect) on Mac. One particular file has started deleting viewports from the Sheet layers when we export them. This feels like a glitch. The Navigation pane suggests that the viewports still exist - but they are no longer on the sheet layer than the Navigation pane says that they are on. I've no idea where to even start diagnosing this problem - any assistance greatly appreciated! Sam