iOS application getting crashed "Could not set up parent class, due to: Invalid generic instantiation" .net MAUI

Question

.net MAUI Project based on .net version 7 getting crashed while I am trying to deploy it on device. Below is the exception I am getting:

Visual Studio for Mac version :17.4(build 2406) .net version: .net 7 iPhone 13, iOS 16.3 below are the packages being used:

Crashlogs: Unhandled Exception: System.TypeLoadException: Could not set up parent class, due to: Invalid generic instantiation assembly:/private/var/containers/Bundle/Application/8849B149-36C8-4750-86DD-2AAC2A958F3D//Microsoft.Maui.dll type:ViewHandler2 member:(null) at CommunityToolkit.Maui.AppBuilderExtensions.<>c.b__0_0(IMauiHandlersCollection h) in /_/src/CommunityToolkit.Maui/AppBuilderExtensions.shared.cs:line 28 at Microsoft.Maui.Hosting.HandlerMauiAppBuilderExtensions.HandlerRegistration.AddRegistration(IMauiHandlersCollection builder) at Microsoft.Maui.Hosting.Internal.MauiHandlersFactory.CreateHandlerCollection(IEnumerable1 registrationActions) at Microsoft.Maui.Hosting.Internal.MauiHandlersFactory..ctor(IEnumerable`1 registrationActions) at Microsoft.Maui.Hosting.HandlerMauiAppBuilderExtensions.<>c.b__1_0(IServiceProvider sp) at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.<…>

Midrash

To begin with, you can try to build in release mode instead of debug mode. If that doesn't work, please help provide more details on this issue like VS version, .NET version, iOS device information and the nuget packages. – Elwaine

You have installed many packages so I can't judge if the issue still exists if add community toolkit package. You can try to create an empty project and add community toolkit package, then determine if the issue still exists. I suspect the issue is caused by the package Telerik.UI.for.Maui. You can refer to .NET MAUI Project - Could not set up parent class, due to: Invalid generic instantiation. – Elwaine

@AlexandarMay-MSFT after further investigation of crash logs i found that there is an issue with CommunityToolkt.Maui package. Pasting the crashlogs in question. – Midrash

If it's related with CommunityToolkt.Maui package, you can create an issue at github.com/CommunityToolkit/Maui/issues for help. – Elwaine

Answer 1

In my case it was caused due to outdated MAUI workloads that was installed on the Mac. See the issue thread on Github for more info. Running the following command updated the workloads and resolved the issue for me (Ended up having to update my Mac and then update XCode to 15.4 as well):

sudo dotnet workload install android ios maui

Amery

Answer 2

Degrading CommunityToolkt.Maui version from 4.0.0 to 3.1 resolves the issue

Outline

It is 2024 and the problem just happened again. I had to downgrade from 9.1.0 to 9.0.3 although I did what CVStyrdom suggested. – Speedometer

Ditto. Had to do the same. But the had workload issues too. This saved me github.com/dotnet/maui/issues/24981#issuecomment-2381922764. I had to uninstall all workloads reinstall and then revert the nuget to 9.0.3. – Parthenope

Just downgrading wasn't enough for me either, deleting the obj and bin folder solved the issue for me. – Bargeboard