Getting an different error than I've seen reported here in both Xcode 16.0 and 16.1 beta 2 (without Legacy Previews): "Cannot preview in this file. Implicitly unwrapped nil value in GeneratedAssetSymbols.swift" I've performed the reporting requested and submitted a feedback: FB15176682

Just tested with the new beta. This is working as of iOS 18 beta 3.

Same issue here, also posted: FB13946288