Just wanted to add a bit to this since I came to this thread looking to resolve why my framework builds did not include simulator binaries for both M1 Macs (ARM) and Intel. I was using the same "xcodebuild archive -scheme StructKit -destination "generic/platform=iOS Simulator" ..." command mentioned before, however for me I only ever saw an intel binary in the resigning framework generated. What ended up being the fix, was that inside my .xcproj file some old version of Xcode has left a default "archs" value for simulators that looked like this: VALID_ARCHS[sdk=iphonesimulator] I removed those from two places in the .xcodeproj file, and after that the xcodebuild command produced a framework that had a fat binary with both ARM and Intel.

One thing you can do in Xcode 12 is to test purchases in the simulator, if you set up a StoreKit Configuration file and enable it in the project scheme... Then you can do the full range of purchase testing in the simulator. On device Sandbox should still present a login (make sure your scheme does not have a StoreKit configuration active if you want to test using Sandbox), if you go to Settings->AppStore are you already logged in to a testing account? If you are it would not present a new login. I get the same crash in Xcode using the Transactions window and clicking on "manage subscriptions", though Xcode 12.2 seems to have a release candidate now and that might fix things.

I'm filing a radar on this issue, as the simulator should load products from AppStoreConnect if a StoreKit configuration profile has not been specified in the Scheme you are running.

@rich SKProducts have been able to load in the simulator right up until my run in iOS 14... indeed, even running from Xcode 12 beta, in an iOS 13.2 simulator SKProducts load just fine. I also test product loads on a device, but that is pretty cumbersome to do all the time compared to using the simulator. Also Sandbox is often pokey at loading SKProducts where the simulator is always pretty much instant. I'm more looking to get a sense from Apple if starting from iOS 14 SKProducts will not load from the App Store, or if this is a bug... I'll file a radar and see what they say I guess.