It sounds like Xcode is hanging while opening the project. If you could file a feedback and include the output of running: sample Xcode in the terminal while Xcode is hung, that would be really helpful. It would also be interesting to know if you can open the files from your project in other apps, to know if the hang is related to accessing the files.

You can create a package by choosing File > New Project … from the main menu, then Package… in the resulting dialog.

Ah, that's frustrating. It would be helpful if you could file a feedback with a CPU sample of AssetCatalogSimulatorAgent You can get a CPU sample either from activity monitor, or by running this in the terminal just before building. sample AssetCatalogSimulatorAgent 120 -wait Does the performance of the build change if you remove all of the groups and layers from the icon?