uno-check error after installing Visual Studio 2026

[mcNets]

I've uninstalled VS 2022 Prev and then I installed VS2026 Insiders.

After installation I run uno-check and I'm getting this error:

¤ Uno Platform Check v1.31.13.0 ¤
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
This tool will check your Uno Platform development environment.
If problems are detected, it will offer the option to try and fix them for you, or suggest a way to fix them yourself.
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
» Synchronizing configuration... ok
» Scheduling appointments... ok

> OpenJDK 11.0 Checkup...
  - 11.0.20.1 (C:\Program Files\Microsoft\jdk-11.0.20.101-hotspot\bin\..)

> Visual Studio 17.12 Checkup...
  - 18.0.0-insiders - C:\Program Files\Microsoft Visual Studio\18\Insiders

> Visual Studio Workloads Checkup...
  - .NET desktop development is installed (18.0.0-insiders)
  - .NET Multi-platform App UI development is installed (18.0.0-insiders)
  - ASP.NET and web development is installed (18.0.0-insiders)

> Android SDK Checkup...
  - emulator (33.1.24)
  - build-tools;35.0.0 (35.0.0)
  - platforms;android-35 (2)
  - system-images;android-35;google_apis;x86_64 (8)
  - platform-tools (36.0.0)
  - cmdline-tools;13.0 (13.0)

> Android Emulator Checkup...
  - Emulator: system-images;android-33;google_apis;x86_64 found.

> .NET SDK Checkup...
  - 7.0.410 - C:\Program Files\dotnet\sdk\7.0.410
  - 8.0.206 - C:\Program Files\dotnet\sdk\8.0.206
  - 8.0.414 - C:\Program Files\dotnet\sdk\8.0.414
  - 9.0.110 - C:\Program Files\dotnet\sdk\9.0.110
  - 10.0.100-rc.1.25451.107 - C:\Program Files\dotnet\sdk\10.0.100-rc.1.25451.107

¬ Skipped: PowerShell Execution Policy (Not required by the current configuration)

¬ Skipped: Windows Python Installation (Not required by the current configuration)

> Windows Long Path Checkup...
  - Long paths are enabled on Windows!

¬ Skipped: Git (Not required by the current configuration)

> Windows Hyper-V Checkup...
  - Hyper-V is configured

> dotnet new Uno Project Command Line Templates Checkup...

> Uno SDK Checkup...

> Edge WebView2 Checkup...
  - Found Edge WebView2 version 140.0.3485.66

> .NET SDK - Workloads (9.0.300) Checkup...
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────


! There were one or more problems detected.
Please review the errors and correct them and run uno-check again.

If I run `dotnet worload list' I get:

➜ dotnet workload list

Versión de carga de trabajo: 10.0.100-manifests.a6e8bec0

Id. de carga de trabajo instalada      Versión del manifiesto                   Origen de la instalación
--------------------------------------------------------------------------------------------------------
android                                36.0.0-rc.1.285/10.0.100-rc.1            VS 18.0.11012.119
ios                                    18.5.10727-net10-rc.1/10.0.100-rc.1      VS 18.0.11012.119
maccatalyst                            18.5.10727-net10-rc.1/10.0.100-rc.1      VS 18.0.11012.119
maui-windows                           10.0.0-rc.1.25452.6/10.0.100-rc.1        VS 18.0.11012.119

It seems that VS2026 have uninstalled .net 9 workloads but, shouldn't uno-check reinstall them?

[jeromelaban]

Thanks for the report. It should be reinstalling them, but can you run with --verbose to get more information? Thanks!

[mcNets]

> .NET SDK Checkup...
SetEnvironmentVariable: DOTNET_ROOT=C:\Program Files\dotnet
SHELL: C:\Program Files\dotnet\dotnet.exe --list-sdks
7.0.410 [C:\Program Files\dotnet\sdk]
8.0.206 [C:\Program Files\dotnet\sdk]
8.0.414 [C:\Program Files\dotnet\sdk]
9.0.110 [C:\Program Files\dotnet\sdk]
10.0.100-rc.1.25451.107 [C:\Program Files\dotnet\sdk]
  - 7.0.410 - C:\Program Files\dotnet\sdk\7.0.410
  - 8.0.206 - C:\Program Files\dotnet\sdk\8.0.206
  - 8.0.414 - C:\Program Files\dotnet\sdk\8.0.414
  - 9.0.110 - C:\Program Files\dotnet\sdk\9.0.110
  - 10.0.100-rc.1.25451.107 - C:\Program Files\dotnet\sdk\10.0.100-rc.1.25451.107
SetEnvironmentVariable: DOTNET_SDK=C:\Program Files\dotnet\sdk\10.0.100-rc.1.25451.107
SetEnvironmentVariable: DOTNET_SDK_VERSION=10.0.100-rc.1.25451.107

¬ Skipped: PowerShell Execution Policy (Not required by the current configuration)

¬ Skipped: Windows Python Installation (Not required by the current configuration)

> Windows Long Path Checkup...
  - Long paths are enabled on Windows!

¬ Skipped: Git (Not required by the current configuration)

> Windows Hyper-V Checkup...
  - Hyper-V is configured

> dotnet new Uno Project Command Line Templates Checkup...

> Uno SDK Checkup...

> Edge WebView2 Checkup...
  - Found Edge WebView2 version 140.0.3485.66

> .NET SDK - Workloads (9.0.300) Checkup...
SHELL: C:\Program Files\dotnet\dotnet.exe workload list --machine-readable
The command could not be loaded, possibly because:
  * You intended to execute a .NET application:
      The application 'workload' does not exist or is not a managed .dll or .exe.
  * You intended to execute a .NET SDK command:
      A compatible .NET SDK was not found.

Requested SDK version: 9.0.300
global.json file: C:\Users\mcnets\AppData\Local\Temp\uno-check-0f7c63f6\global.json

Installed SDKs:

Install the [9.0.300] .NET SDK or update [C:\Users\mcnets\AppData\Local\Temp\uno-check-0f7c63f6\global.json] to match an installed SDK.
7.0.410 [C:\Program Files\dotnet\sdk]
8.0.206 [C:\Program Files\dotnet\sdk]
8.0.414 [C:\Program Files\dotnet\sdk]

Learn about SDK resolution:
https://aka.ms/dotnet/sdk-not-found
9.0.110 [C:\Program Files\dotnet\sdk]
10.0.100-rc.1.25451.107 [C:\Program Files\dotnet\sdk]
System.Exception: Workload command failed: `dotnet workload list --machine-readable`
  at async Task<string[[]]> DotNetCheck.DotNet.DotNetWorkloadManager.GetInstalledWorkloads() in /_/UnoCheck/DotNet/
     DotNetWorkloadManager.cs:109
  at void System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
  at void System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
  at void System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
  at TResult System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
  at async Task<DiagnosticResult> DotNetCheck.Checkups.DotNetWorkloadsCheckup.Examine(SharedState history) in
     /_/UnoCheck/Checkups/DotNetWorkloadsCheckup.cs:103
  at void System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
  at void System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
  at void System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
  at TResult System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
  at async Task<int> DotNetCheck.Cli.CheckCommand.ExecuteAsync(CommandContext context, CheckSettings settings) in
     /_/UnoCheck/CheckCommand.cs:221
────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Checkup had Error status: dotnetworkloads-9.0.300

dotnetworkloads-9.0.300: Workload command failed: `dotnet workload list --machine-readable`
! There were one or more problems detected.
Please review the errors and correct them and run uno-check again.

Press Enter to finish...

and this is the result of dotnet workload list --machine-readable:

➜ dotnet workload list --machine-readable
{"installed":[],"updateAvailable":[]}

[mcNets]

Re-installing .net9 solves it.