SwiftUI Preview fails - System Policy: deny(1) file-read-data

I have yet to see a SwiftUI Preview generated successfully in my environment - MacOS 10.15.7, Xcode 12.1.

I always get "Cannot preview in the file -- Failed to update preview." When I pull the diagnostic report (in this case from an Apple SwiftUI tutorial) and examine the mass of data, I find the following snippet from the sandbox.txt file:
Code Block
2020-10-24 14:01:11.326639-0700 0x15c471 Error 0x0 233 0 sandboxd: (CoreSymbolication) Region <private> [7fff209d6f28 -> 4d67) outside of relocations in mmap SOD
2020-10-24 14:01:11.332566-0700 0x15c471 Error 0x0 233 0 sandboxd: [com.apple.sandbox.reporting:violation] Sandbox: Landmarks(22842) System Policy: deny(1) file-read-data /Users/kgomara/Documents/OMaraConsultingAssoc/Projects/CreatingAndCombiningViews/Complete/Landmarks/Build/Intermediates.noindex/Previews/Landmarks/Intermediates.noindex/CreatingAndCombiningViews.build/Debug-iphonesimulator/Landmarks.build/Objects-normal/x86_64/ContentView.2.preview-thunk.dylib
Violation: System Policy: deny(1) file-read-data /Users/kgomara/Documents/OMaraConsultingAssoc/Projects/CreatingAndCombiningViews/Complete/Landmarks/Build/Intermediates.noindex/Previews/Landmarks/Intermediates.noindex/CreatingAndCombiningViews.build/Debug-iphonesimulator/Landmarks.build/Objects-normal/x86_64/ContentView.2.preview-thunk.dylib
Process: Landmarks [22842]


I don't think it's Unix permissions, but to be sure I chmod'd 777 from /User to the .dylib - which didn't help.

I'm pretty sure the System policy violation is the root cause - but how do I fix it?
SwiftUI Preview fails - System Policy: deny(1) file-read-data
 
 
Q