Xamarin.iOS cannot create/open storyboard

Question

We have an issue with creating a storyboard in Xamarin.iOS . We have paired to Mac and on the VS GUI it says it is connected. When we try to create (or open an existing storyboard in new project) we get the same error:

System.AggregateException: One or more errors occurred. ---> System.AggregateException: One or more errors occurred. ---> MonoTouch.Design.Client.InvalidSessionException: Error in the application.
   at MonoTouch.Design.Client.ServerProcessConnection.SendRequest(CommandRequest req, Boolean throwIfNotRunning) in E:\A\_work\79\s\Xamarin.Designer.iOS\MonoTouch.Design.Client\Connection\ServerProcessConnection.cs:line 235
   at MonoTouch.Design.Client.ServerProcessConnection.SendRequest[TResponse](CommandRequest req, Boolean throwIfNotRunning) in E:\A\_work\79\s\Xamarin.Designer.iOS\MonoTouch.Design.Client\Connection\ServerProcessConnection.cs:line 252
   at MonoTouch.Design.Client.ServerProcessConnection.CreateSession() in E:\A\_work\79\s\Xamarin.Designer.iOS\MonoTouch.Design.Client\Connection\ServerProcessConnection.cs:line 111
   at MonoTouch.Design.Client.ServerProcessConnection.<CreateSessionAsync>b__28_0() in E:\A\_work\79\s\Xamarin.Designer.iOS\MonoTouch.Design.Client\Connection\ServerProcessConnection.cs:line 116
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception exceptionObject)
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at System.Threading.Tasks.Task`1.get_Result()
   at MonoTouch.Design.Client.IPhoneDesignerSession.<>c__DisplayClass289_1`1.<EnsureSession>b__1(Task`1 t) in E:\A\_work\79\s\Xamarin.Designer.iOS\MonoTouch.Design.Client\IPhoneDesignerSession.cs:line 2070
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait()
   at MonoTouch.Design.Client.IPhoneDesignerSession.<>c__DisplayClass289_0`1.<EnsureSession>b__0() in E:\A\_work\79\s\Xamarin.Designer.iOS\MonoTouch.Design.Client\IPhoneDesignerSession.cs:line 2136
   at System.Threading.Tasks.Task`1.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
--- End of stack trace from previous location where exception was thrown ---
[Truncated here]

The version of both VS on Windows 10 and Catalina is the latest one (cannot update anymore) and Xcode is version 11.3

I've read a lot of articles online saying to update and restart the IDE and it should be fine, but I cannot do anything...

Does anyone have any idea how to solve this?

Answer 1

The issue is, it seems, in macOS version.
I've talked with some of my coworkers who use a different type of software (Flash Builder) and he said he had similar issues with Catalina macOS.
So I switched back to Mojave , updated to 10.4.16 . and installed Xcode and VSforMac and it finally works (or works for iPhone 8 iOS 13)