I\'ve been dealing with this issue when I run my app via debug on simulator, as soon as I upgraded to the latest Xcode 8.0 and OS version 10.11.6. Error below:
Appli
From Brendan Zagaeski's comment in https://bugzilla.xamarin.com/show_bug.cgi?id=44361#c3
In further study of the workaround, I found that it was not in fact necessary to enable "Keychain Access Groups" in the Entitlements.plist file. It was sufficient just to add any Entitlements.plist file (even one with no property keys).
Workaround in Xamarin Studio on Mac
Add an "iOS > Property List" to the project and name it "Entitlements.plist".
Add the "Entitlements.plist" file under "Project Options > Build > iOS Bundle Signing > Custom Entitlements".
(Be sure to follow step 5 for the "iPhoneSimulator" configuration, and not just the "iPhone" configuration.)
- Save the project properties and re-deploy the app to the simulator.
Workaround in Visual Studio
Add a new "Apple > Misc > Entitlements.plist" file to the top level of the project.
Add the "Entitlements.plist" file under "Project properties > iOS Bundle Signing > Custom Entitlements".
(Be sure to follow step 2 for the "iPhoneSimulator" configuration, and not just the "iPhone" configuration.)
- Save the project properties and re-deploy the app to the simulator.
(The original text from the link mentioned a Xamarin VS file selector bug that has since been fixed)