Try it in CC 2014.
CC 2015 is the first part of a major change to AE under the hood. Trying in CC 2014 will help us see if it's anything to do with the new architecture in AE or something else.
When you get crashes, what do they say?
Thanks for the reply.
This is a work flow I've used for years (and I go back to After Effects 3.1, before ram previews![I think])
I didn't take a screen shot of the crash report, but did send to Adobe. The work around I've found is to duplicate the first folder, not the subsequent duplicates.
I will take guidance if anybody has any better ideas.
Thanks, Neil W
Szalam is being far too forgiving of Adobe, as per usual, so you've missed the important parts because he's obscured them with obsequiousness to the powers that be.
AE 2015 is a bug riddled NIGHTMARE, in alpha state (not beta) and just about all manner of things will be AE's fault, not yours.
Having said that, AE 2014 on a Mac is also wrought with issues, mostly different ones, but some of them are the same, too.
Generally speaking, Adobe stopped giving primary care to Mac users the moment they planned to goto a subscription model, which was about the same time they got pasted for Flash performance on the iPhone. Probably not a coincidence.
There are threads with people complaining about Mac performance going back at least 5 years.