Many thanks.

For the records: I use now the Prefrerences Utilities. The readBool code was already given by Quinn above. Here is my writeBool code: func writeBool(domain: String, key: String, value: Bool) { let appID = domain as CFString let cfKey = key as CFString let cfValue: CFPropertyList = value as CFBoolean CFPreferencesSetValue(cfKey, cfValue, appID, kCFPreferencesCurrentUser, kCFPreferencesAnyHost) CFPreferencesSynchronize(appID, kCFPreferencesCurrentUser, kCFPreferencesAnyHost) }

Many thanks Quinn. I prefer plain Swift Classes and therefore I did not look at the Preferences Utilities. I will look into this and I agree that this is a much better solution than using the shell command.

Strange: In my test application I removed "Apple Sandbox" and now it works here. Using the same settings it does not work in my real app. I guess there is a wrong Xcode setting for my target. Need to investigate…

Finally I was able to solve this via GeometryProxy with some math. It could be hard to wrap the brain around local and global coordinates relationship.

I did several times a clean build. My development machine is a MacBook Pro M1 on Monterey and therefore I cannot use Xcode 12 anymore. I wan to copy just the application to the older Mac and not use Xcode on that machine. The test project was also created on my development machine. Any yes: The error message is really strange.

Meanwhile I got it working. Now I use SwiftSMTP which works well in background. See “swift-smtp/Sources/SwiftSMTPCLI/main.swift“ for sample code how to use it.