Since I upgraded, two days ago, to the latest version of Visual Studio for Mac the XAML previewer no longer renders for iOS (Android still works), This is the stack trace it renders instead:
System.AggregateException: One or more errors occurred. ---> System.AggregateException: One or more errors occurred. ---> MonoTouch.Design.Client.InvalidSessionException: Exception of type 'MonoTouch.Design.Client.InvalidSessionException' was thrown. ---> Foundation.NSErrorException: Exception of type 'Foundation.NSErrorException' was thrown.
at MonoTouch.Hosting.SlimSession.LaunchApplicationImpl (System.String bundleId, System.String[] arguments) [0x001a9] in <8a34bfb579844fbaa8516068fec2ce02>:0
at MonoTouch.Hosting.Session.LaunchApplication (System.String bundleId, System.String[] arguments) [0x00006] in <8a34bfb579844fbaa8516068fec2ce02>:0
at MonoTouch.Design.Client.Mac.MacServerProcessConnection.EnsureServerRunning (System.Boolean throwIfNotRunning) [0x0017d] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client.Mac/MacServerProcessConnection.cs:313
--- End of inner exception stack trace ---
at MonoTouch.Design.Client.Mac.MacServerProcessConnection.EnsureServerRunning (System.Boolean throwIfNotRunning) [0x001d0] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client.Mac/MacServerProcessConnection.cs:323
at MonoTouch.Design.Client.ServerProcessConnection.SendRequestCore (MonoTouch.Design.CommandRequest request, System.Boolean throwIfNotRunning) [0x00056] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:271
at MonoTouch.Design.Client.ServerProcessConnection.SendRequest (MonoTouch.Design.CommandRequest req, System.Boolean throwIfNotRunning) [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:219
at MonoTouch.Design.Client.ServerProcessConnection.SendRequest[TResponse] (MonoTouch.Design.CommandRequest req, System.Boolean throwIfNotRunning) [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:241
at MonoTouch.Design.Client.ServerProcessConnection.CreateSession () [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:109
at MonoTouch.Design.Client.ServerProcessConnection.b__24_0 () [0x00000] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:114
at System.Threading.Tasks.Task1[TResult].InnerInvoke () [0x0000f] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680 at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 --- End of inner exception stack trace --- at System.Threading.Tasks.Task.ThrowIfExceptional (System.Boolean includeTaskCanceledExceptions) [0x00013] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2159 at System.Threading.Tasks.Task1[TResult].GetResultCore (System.Boolean waitCompletionNotification) [0x0002b] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:562
at System.Threading.Tasks.Task1[TResult].get_Result () [0x00000] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:532 at MonoTouch.Design.Client.IPhoneDesignerSession+<>c__DisplayClass265_11[TResult].b__1 (System.Threading.Tasks.Task1[TResult] t) [0x00012] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/IPhoneDesignerSession.cs:1858 at System.Threading.Tasks.ContinuationResultTaskFromResultTask2[TAntecedentResult,TResult].InnerInvoke () [0x00024] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/TaskContinuation.cs:207
at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502
--- End of inner exception stack trace ---
at System.Threading.Tasks.Task.ThrowIfExceptional (System.Boolean includeTaskCanceledExceptions) [0x00013] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2159
at System.Threading.Tasks.Task.Wait (System.Int32 millisecondsTimeout, System.Threading.CancellationToken cancellationToken) [0x00043] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:3189
at System.Threading.Tasks.Task.Wait () [0x00000] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:3054
at MonoTouch.Design.Client.IPhoneDesignerSession+<>c__DisplayClass265_01[TResult].<EnsureSession>b__0 () [0x002bb] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/IPhoneDesignerSession.cs:1919 at System.Threading.Tasks.Task1[TResult].InnerInvoke () [0x0000f] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680
at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:152
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x00037] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:187
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x00028] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:156
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x00008] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:128
at System.Runtime.CompilerServices.TaskAwaiter1[TResult].GetResult () [0x00000] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:357 at Xamarin.Designer.Forms.Preview.iOSXamlRenderer+<RenderXamls>d__2.MoveNext () [0x001ed] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.Forms/Xamarin.Designer.Forms.Preview/iOS/iOSXamlRenderer.cs:56 ---> (Inner Exception #0) System.AggregateException: One or more errors occurred. ---> MonoTouch.Design.Client.InvalidSessionException: Exception of type 'MonoTouch.Design.Client.InvalidSessionException' was thrown. ---> Foundation.NSErrorException: Exception of type 'Foundation.NSErrorException' was thrown. at MonoTouch.Hosting.SlimSession.LaunchApplicationImpl (System.String bundleId, System.String[] arguments) [0x001a9] in <8a34bfb579844fbaa8516068fec2ce02>:0 at MonoTouch.Hosting.Session.LaunchApplication (System.String bundleId, System.String[] arguments) [0x00006] in <8a34bfb579844fbaa8516068fec2ce02>:0 at MonoTouch.Design.Client.Mac.MacServerProcessConnection.EnsureServerRunning (System.Boolean throwIfNotRunning) [0x0017d] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client.Mac/MacServerProcessConnection.cs:313 --- End of inner exception stack trace --- at MonoTouch.Design.Client.Mac.MacServerProcessConnection.EnsureServerRunning (System.Boolean throwIfNotRunning) [0x001d0] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client.Mac/MacServerProcessConnection.cs:323 at MonoTouch.Design.Client.ServerProcessConnection.SendRequestCore (MonoTouch.Design.CommandRequest request, System.Boolean throwIfNotRunning) [0x00056] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:271 at MonoTouch.Design.Client.ServerProcessConnection.SendRequest (MonoTouch.Design.CommandRequest req, System.Boolean throwIfNotRunning) [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:219 at MonoTouch.Design.Client.ServerProcessConnection.SendRequest[TResponse] (MonoTouch.Design.CommandRequest req, System.Boolean throwIfNotRunning) [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:241 at MonoTouch.Design.Client.ServerProcessConnection.CreateSession () [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:109 at MonoTouch.Design.Client.ServerProcessConnection.<CreateSessionAsync>b__24_0 () [0x00000] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:114 at System.Threading.Tasks.Task1[TResult].InnerInvoke () [0x0000f] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680
at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502
--- End of inner exception stack trace ---
at System.Threading.Tasks.Task.ThrowIfExceptional (System.Boolean includeTaskCanceledExceptions) [0x00013] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2159
at System.Threading.Tasks.Task1[TResult].GetResultCore (System.Boolean waitCompletionNotification) [0x0002b] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:562 at System.Threading.Tasks.Task1[TResult].get_Result () [0x00000] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:532
at MonoTouch.Design.Client.IPhoneDesignerSession+<>c__DisplayClass265_11[TResult].<EnsureSession>b__1 (System.Threading.Tasks.Task1[TResult] t) [0x00012] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/IPhoneDesignerSession.cs:1858
at System.Threading.Tasks.ContinuationResultTaskFromResultTask2[TAntecedentResult,TResult].InnerInvoke () [0x00024] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/TaskContinuation.cs:207 at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 ---> (Inner Exception #0) MonoTouch.Design.Client.InvalidSessionException: Exception of type 'MonoTouch.Design.Client.InvalidSessionException' was thrown. ---> Foundation.NSErrorException: Exception of type 'Foundation.NSErrorException' was thrown. at MonoTouch.Hosting.SlimSession.LaunchApplicationImpl (System.String bundleId, System.String[] arguments) [0x001a9] in <8a34bfb579844fbaa8516068fec2ce02>:0 at MonoTouch.Hosting.Session.LaunchApplication (System.String bundleId, System.String[] arguments) [0x00006] in <8a34bfb579844fbaa8516068fec2ce02>:0 at MonoTouch.Design.Client.Mac.MacServerProcessConnection.EnsureServerRunning (System.Boolean throwIfNotRunning) [0x0017d] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client.Mac/MacServerProcessConnection.cs:313 --- End of inner exception stack trace --- at MonoTouch.Design.Client.Mac.MacServerProcessConnection.EnsureServerRunning (System.Boolean throwIfNotRunning) [0x001d0] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client.Mac/MacServerProcessConnection.cs:323 at MonoTouch.Design.Client.ServerProcessConnection.SendRequestCore (MonoTouch.Design.CommandRequest request, System.Boolean throwIfNotRunning) [0x00056] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:271 at MonoTouch.Design.Client.ServerProcessConnection.SendRequest (MonoTouch.Design.CommandRequest req, System.Boolean throwIfNotRunning) [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:219 at MonoTouch.Design.Client.ServerProcessConnection.SendRequest[TResponse] (MonoTouch.Design.CommandRequest req, System.Boolean throwIfNotRunning) [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:241 at MonoTouch.Design.Client.ServerProcessConnection.CreateSession () [0x00001] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:109 at MonoTouch.Design.Client.ServerProcessConnection.<CreateSessionAsync>b__24_0 () [0x00000] in /Users/vsts/agent/2.124.0/work/1/s/Xamarin.Designer.iOS/MonoTouch.Design.Client/Connection/ServerProcessConnection.cs:114 at System.Threading.Tasks.Task1[TResult].InnerInvoke () [0x0000f] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680
at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/data/lanes/4992/mono-mac-sdk/external/bockbuild/builds/mono-x64/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 <---
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