Can't install necessary dotnet workloads

[Eatham532]

Sorry in advance if this is the wrong place to ask this question.

When running the command dotnet workload install to download the necessary workloads for uno I get installation errors. Here is a log from powershell.

uno-log.txt

When manually running dotnet workload install macos I get this warning at the end.
Warning: Workload garbage collection failed with error: Object reference not set to an instance of an object..

When manually running dotnet workload install maccatylist it begins to rollback the action. With the same error Object reference not set to an instance of an object

[Youssef1313]

Try unoplatform/uno.check#50 (comment)

[Eatham532]

I did that before. Didn't seem to fix it. But I will try to do it again.

[jeromelaban]

@Eatham532 thanks for the update. Why do you need to run dotnet workloads restore ? Does uno-check indicate that all is installed?

[Eatham532]

uno-check says that my workloads are not installed. And when trying to build the default template app I get errors about the workloads. So I tried installing them manually using dotnet workloads install which failed.

[Eatham532]

Could it be because I am using .net 7?

[nickrandolph]

@Eatham532 do you have any preview versions of Visual Studio installed? Also, can you run "dotnet --info" and share results here

[Eatham532]

No, I do not have any preview versions installed. The results from running dotnet --info:

 Version:   7.0.203
 Commit:    5b005c19f5

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22621
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\7.0.203\

Host:
  Version:      7.0.5
  Architecture: x64
  Commit:       8042d61b17

.NET SDKs installed:
  7.0.203 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.15 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.16 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.5 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download```

[jeromelaban]

This is unfortunately a case of workloads not working properly. Aside from uninstalling all .NET versions and all VS instances (that is until .NET 8 with the new dotnet workload cleanup option that may help) and reinstalling everything, we cannot provide much more options.

This is a topic that is very frequent on the MAUI repo: https://github.com/dotnet/maui/issues?q=is%3Aissue+is%3Aopen+workload

GitHub

Issues · dotnet/maui

.NET MAUI is the .NET Multi-platform App UI, a framework for building native device applications spanning mobile, tablet, and desktop. - Issues · dotnet/maui

[Eatham532]

I managed to fix this issue. There seemed to be some issue with the workloads I currently had installed. And it seems when removing dotnet and visual studio the workloads don't get removed. I created a backup of C:\ProgramData\dotnet\workloads and removed the folder. Then when running uno-check the workloads installed successfully.

I also moved back the workloads I made a backup with before in case there were some that were not installed when running uno-check and made sure to click skip when there were two of the same files.

[jeromelaban]

Thanks for the update!

[Mertsch]

The issue still exists in 2025 and yes, deleting C:\ProgramData\dotnet\workloads and running dotnet workload update fixes the issue.