can't build, won't build !@?

[John Dixon]

Using LC 7.1 and Xcode 6.4, I have no problem getting a stack to run in the simulator or on a device...

Using LC 7.1.1(RC3) or LC 8,0 (dp 8) and Xcode 7.1, I get error dialogs that are telling me 'Unable to build for simulation'  as files cannot be copied...

If I return to LC 7.1 and Xcode 8.4, the problem goes away again...

Does anyone have any idea how I have upset the 'liveCode' gods with my latest offering ?

Screen shot of the dialog :-
http://www.ihouse.on-rev.com/cantbuildwontbuild.jpg